Logarithmic derivative quantitative analysis method and device for dominant oscillation mode of power system

Abstract

The invention relates to the technical field of power system stability analysis, in particular to a quantitative analysis method and device for logarithmic derivatives of a dominant oscillation mode of a power system, and the method comprises the steps: determining the frequency step size of the power system, and obtaining the logarithmic derivative of an admittance matrix determinant according to the frequency step size; acquiring a real part extreme point and an adjacent frequency point of the logarithmic derivative, and pre-identifying a dominant oscillation mode of the power system according to the real part extreme point and the adjacent frequency point; and calculating oscillation damping and frequency of the power system according to the dominant oscillation mode. Therefore, the problem that the accuracy of oscillation source identification and system stability evaluation is affected due to inaccurate estimation of key parameters such as the damping ratio and the oscillation frequency in the dominant oscillation mode due to the fact that the influence of the frequency step length on the parameter identification precision is not fully considered in an electric power system oscillation analysis method is solved.

Description

Technical Field

[0001] The present application relates to the technical field of power system stability analysis, and in particular to a logarithmic derivative quantitative analysis method and device for a dominant oscillation mode of a power system. Background Art

[0002] As the proportion of renewable energy access continues to rise, the structure and dynamic characteristics of power systems are becoming increasingly complex. The dominant oscillation modes are gradually exhibiting characteristics such as broadband, weak damping, and multimodal behavior, seriously threatening the stability and safety of system operations. Impedance analysis, as a mainstream method for assessing oscillation stability, has been widely used in grid-connected system stability research due to its excellent visualization capabilities and theoretical foundation.

[0003] However, although relevant technologies can identify potential oscillation risks in power systems to a certain extent, they generally do not consider the impact of frequency step size on analysis accuracy. Sampling errors are easily introduced in the frequency domain discrete modeling process, which may lead to inaccurate estimation of key parameters such as the damping ratio and oscillation frequency of the dominant oscillation mode, thereby directly affecting the accuracy and reliability of oscillation source identification, stability assessment and control strategy design. This problem needs to be urgently addressed. Summary of the Invention

[0004] The present application provides a logarithmic derivative quantitative analysis method and device for the dominant oscillation mode of an electric power system, in order to solve the problem in the related art that the electric power system oscillation analysis method does not consider the influence of the frequency step on the analysis accuracy, and is prone to introduce sampling errors in the frequency domain discrete modeling process, resulting in inaccurate estimation of key parameters such as the damping ratio and oscillation frequency, thereby directly affecting the accuracy and reliability of oscillation source identification, stability assessment and control strategy design.

[0005] A first aspect embodiment of the present application provides a method for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of an electric power system, comprising the following steps: determining the frequency step of the electric power system, and obtaining the logarithmic derivative of the determinant of the admittance matrix according to the frequency step; obtaining the real extreme point of the logarithmic derivative and its adjacent frequency points, and pre-identifying the dominant oscillation mode of the electric power system according to the real extreme point and its adjacent frequency points; and calculating the oscillation damping and frequency of the electric power system according to the dominant oscillation mode.

[0006] Through the above technical means, the real part extreme points and their adjacent frequency points are used to pre-identify the dominant oscillation mode of the power system, and then the oscillation damping and frequency of the power system are calculated. The dominant mode can be quickly located and parameters extracted based on the frequency domain response characteristics. By identifying the local extreme points of the real part of the logarithmic derivative on the frequency axis and combining the changing trends of its adjacent frequency points, the potential area where the dominant zero point is located can be preliminarily locked as the candidate frequency interval of the dominant mode. The damping ratio and oscillation frequency corresponding to the frequency are further calculated, and the dominant oscillation mode can be quantitatively analyzed, thereby providing an efficient and low-cost technical path for system oscillation stability assessment, online early warning and control strategy design.

[0007] Optionally, in one embodiment of the present application, the calculation formula of the logarithmic derivative is:

[0008]

[0009] Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

[0010] Through the above technical means, the differential approximation is used to calculate the logarithmic derivative of the system admittance matrix, which can significantly reduce the computational complexity while ensuring the analysis accuracy, avoiding explicit derivation or symbolic processing of the high-dimensional admittance matrix, thereby improving the computational efficiency and engineering applicability of the dominant oscillation mode identification, and providing efficient data support for subsequent damping evaluation and oscillation early warning.

[0011] Optionally, in one embodiment of the present application, the pre-identification of the dominant oscillation mode of the power system based on the real part extreme point and its adjacent frequency points includes: extracting the real part-frequency characteristic curve and the imaginary part-frequency characteristic curve of the logarithmic derivative to obtain the real part and the imaginary part, and determining the candidate frequency point of the dominant oscillation mode; calculating the slope of the imaginary part of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point based on the real part, the imaginary part, and the candidate frequency point; and determining the dominant oscillation mode based on the real part and the imaginary part slope of the logarithmic derivative.

[0012] Through the above technical means, the imaginary part slope of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point is calculated based on the real part, imaginary part, and candidate frequency point, and then the dominant oscillation mode is determined. The law that the logarithmic derivative curve presents a characteristic inflection point or change trend near the dominant modal frequency can be used to achieve accurate discrimination of the dominant modal frequency position. At the same time, by introducing the imaginary part slope as an auxiliary judgment indicator, the ability to identify sensitive areas of the modal frequency response can be enhanced, and local disturbances caused by non-dominant modes can be further eliminated, thereby improving the accuracy and stability of the dominant oscillation mode identification.

[0013] Optionally, in one embodiment of the present application, the calculating of the oscillation damping and frequency of the power system according to the dominant oscillation mode includes: within the dominant mode frequency neighborhood, selecting the real and imaginary data of the logarithmic derivatives of the candidate frequency points and the adjacent frequency points to fit using a preset fitting formula to solve the oscillation damping and frequency.

[0014] Through the above technical means, by performing nonlinear fitting on the real and imaginary parts of the logarithmic derivatives of the candidate frequency points and adjacent frequency points, key parameters such as the oscillation frequency and damping ratio can be effectively extracted, thereby improving the accuracy of modal identification and providing efficient and reliable parameter support for power system oscillation control.

[0015] Optionally, in one embodiment of the present application, the fitting formula is:

[0016]

[0017] stω∈{ω a -Δω,ω a ,ω a +Δω}

[0018] Among them, w Re 、w Im Represents the weight coefficient of the real and imaginary parts of the logarithmic derivative; ω a Indicates candidate frequency points; α i 、ω i They represent the damping and frequency of the i-th dominant zero / pole of the system respectively.

[0019] Through these technical approaches, using the weight coefficients for fitting the real and imaginary parts of the logarithmic derivative, combined with candidate frequency points to generate a fitting formula, we can achieve comprehensive modeling of frequency-domain response characteristics and accurate fitting of the dominant oscillation mode. By assigning different weights to the real and imaginary parts, we help balance their contributions during the fitting process, enhancing overall sensitivity to oscillation frequency and damping characteristics. Furthermore, constructing a local fitting interval based on the candidate frequency points effectively reduces interference from non-dominant modes and improves the accuracy of identifying the dominant modal response characteristics, thereby achieving highly robust and accurate oscillation parameter extraction.

[0020] The second aspect of the present application provides a device for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of an electric power system, including: an acquisition module for determining the frequency step of the electric power system and obtaining the logarithmic derivative of the determinant of the admittance matrix according to the frequency step; an identification module for obtaining the real part extreme point and its adjacent frequency point of the logarithmic derivative, and pre-identifying the dominant oscillation mode of the electric power system according to the real part extreme point and its adjacent frequency point; and an analysis module for calculating the oscillation damping and frequency of the electric power system according to the dominant oscillation mode.

[0021] Through the above technical means, the real part extreme points and their adjacent frequency points are used to pre-identify the dominant oscillation mode of the power system, and then the oscillation damping and frequency of the power system are calculated. The dominant mode can be quickly located and parameters extracted based on the frequency domain response characteristics. By identifying the local extreme points of the real part of the logarithmic derivative on the frequency axis and combining the changing trends of its adjacent frequency points, the potential area where the dominant zero point is located can be preliminarily locked as the candidate frequency interval of the dominant mode. The damping ratio and oscillation frequency corresponding to the frequency are further calculated, and the dominant oscillation mode can be quantitatively analyzed, thereby providing an efficient and low-cost technical path for system oscillation stability assessment, online early warning and control strategy design.

[0022] Optionally, in one embodiment of the present application, the calculation formula of the logarithmic derivative is:

[0023]

[0024] Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

[0025] Through the above technical means, the differential approximation is used to calculate the logarithmic derivative of the system admittance matrix, which can significantly reduce the computational complexity while ensuring the analysis accuracy, avoiding explicit derivation or symbolic processing of the high-dimensional admittance matrix, thereby improving the computational efficiency and engineering applicability of the dominant oscillation mode identification, and providing efficient data support for subsequent damping evaluation and oscillation early warning.

[0026] Optionally, in one embodiment of the present application, the identification module includes: a determination unit for extracting the real part-frequency characteristic curve and the imaginary part-frequency characteristic curve of the logarithmic derivative to obtain the real part and the imaginary part, and determine the candidate frequency point of the dominant oscillation mode; a calculation unit for calculating the slope of the imaginary part of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point based on the real part, the imaginary part, and the candidate frequency point; and a judgment unit for judging the dominant oscillation mode based on the real part and the imaginary part slope of the logarithmic derivative.

[0027] Through the above technical means, the imaginary part slope of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point is calculated based on the real part, imaginary part, and candidate frequency point, and then the dominant oscillation mode is determined. The law that the logarithmic derivative curve presents a characteristic inflection point or change trend near the dominant modal frequency can be used to achieve accurate discrimination of the dominant modal frequency position. At the same time, by introducing the imaginary part slope as an auxiliary judgment indicator, the ability to identify sensitive areas of the modal frequency response can be enhanced, and local disturbances caused by non-dominant modes can be further eliminated, thereby improving the accuracy and stability of the dominant oscillation mode identification.

[0028] Optionally, in one embodiment of the present application, the analysis module includes: a solution unit, used to select the real and imaginary data of the logarithmic derivatives of the candidate frequency points and the adjacent frequency points within the dominant mode frequency neighborhood to fit using a preset fitting formula to solve the oscillation damping and frequency.

[0029] Through the above technical means, by performing nonlinear fitting on the real and imaginary parts of the logarithmic derivatives of the candidate frequency points and adjacent frequency points, key parameters such as the oscillation frequency and damping ratio can be effectively extracted, thereby improving the accuracy of modal identification and providing efficient and reliable parameter support for power system oscillation control.

[0030] Optionally, in one embodiment of the present application, the fitting formula is:

[0031]

[0032] stω∈{ω a -Δω,ω a ,ω a +Δω}

[0033] Among them, w Re 、w Im Represents the weight coefficient of the real and imaginary parts of the logarithmic derivative; ω a Indicates candidate frequency points; α i 、ω i They represent the damping and frequency of the i-th dominant zero / pole of the system respectively.

[0034] Through these technical approaches, using the weight coefficients for fitting the real and imaginary parts of the logarithmic derivative, combined with candidate frequency points to generate a fitting formula, we can achieve comprehensive modeling of frequency-domain response characteristics and accurate fitting of the dominant oscillation mode. By assigning different weights to the real and imaginary parts, we help balance their contributions during the fitting process, enhancing overall sensitivity to oscillation frequency and damping characteristics. Furthermore, constructing a local fitting interval based on the candidate frequency points effectively reduces interference from non-dominant modes and improves the accuracy of identifying the dominant modal response characteristics, thereby achieving highly robust and accurate oscillation parameter extraction.

[0035] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system as described in the above embodiment.

[0036] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the above-mentioned logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system.

[0037] The fifth aspect of the present application provides a computer program product, including a computer program, which, when executed, is used to implement the above-mentioned logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0040] Figure 1 This is a flow chart of a logarithmic derivative quantitative analysis method of a dominant oscillation mode of a power system provided in accordance with an embodiment of the present application;

[0041] Figure 2 Schematic diagram of a block diagram of a device for quantitatively analyzing the logarithmic derivative of a dominant oscillation mode of a power system according to an embodiment of the present application;

[0042] Figure 3 The figure is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application.

[0043] Reference numerals:

[0044] 10 - Logarithmic derivative quantitative analysis device of the dominant oscillation mode of the power system; 100 - Acquisition module, 200 - Identification module, 300 - Analysis module; 301 - Memory, 302 - Processor, 303 - Communication interface. DETAILED DESCRIPTION

[0045] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0046] The following describes a method and apparatus for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of the power system according to an embodiment of the present application with reference to the accompanying drawings. In response to the technical problem that the power system oscillation analysis method mentioned in the above background technology does not consider the influence of the frequency step on the analysis accuracy, and is prone to introducing sampling errors in the frequency domain discrete modeling process, resulting in inaccurate estimation of key parameters such as the damping ratio and the oscillation frequency, thereby directly affecting the accuracy and reliability of oscillation source identification, stability assessment, and control strategy design, the present application provides a method for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of the power system. In this method, the dominant oscillation mode of the power system is pre-identified based on the extreme point of the real part of the logarithmic derivative and its adjacent frequency points, and then the oscillation damping and frequency of the power system are calculated. Under the premise of considering the frequency step, the logarithmic derivative can be improved based on the determinant of the admittance matrix to achieve accurate identification of the dominant oscillation mode, quantitatively obtain key parameters such as oscillation damping and frequency, and improve the sensitivity and accuracy of oscillation mode identification, thereby providing technical support for the analysis and prevention of broadband oscillations in the power system. This solves the problem that the power system oscillation analysis method does not fully consider the impact of the frequency step on the parameter identification accuracy, which easily leads to inaccurate estimation of key parameters such as the damping ratio and oscillation frequency in the dominant oscillation mode, thereby affecting the accuracy of oscillation source identification and system stability assessment.

[0047] Specifically, Figure 1 A flow chart of a logarithmic derivative quantitative analysis method for a dominant oscillation mode of a power system provided in an embodiment of the present application.

[0048] like Figure 1 As shown in FIG, the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system includes the following steps:

[0049] In step S101 , the frequency step of the power system is determined, and the logarithmic derivative of the determinant of the admittance matrix is ​​obtained according to the frequency step.

[0050] The frequency step size refers to the interval between two adjacent frequency sampling points when discrete sampling is performed on the frequency range. The frequency step size can be 1 Hz or 1.2 Hz. It can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0051] It's important to note that admittance represents the response of an electrical component to current flow. It's the inverse of impedance and is typically a complex number, consisting of real conductance and imaginary susceptance. Based on the relationship between node voltage and injected current, a node admittance matrix can be constructed, which comprehensively describes the topology and electrical characteristics of a power grid.

[0052] As a specific example, the embodiment of the present application is aimed at a power system containing a high proportion of power electronic equipment. First, a certain frequency step is set to establish a frequency domain admittance model of each component (such as photovoltaic inverters, wind turbine converters, flexible DC converter stations, etc.) (which can be obtained through but not limited to frequency domain small signal modeling, frequency scanning experiments, etc.).

[0053] Furthermore, the embodiments of the present application can aggregate the element admittances into a system-level admittance matrix Y(ω) through network topology relationships.

[0054] Specifically, in an embodiment of the present application, the determinant of the admittance matrix can be expressed as G(ω)=det[Y(ω)], and the logarithmic derivative of the determinant G(ω) can be defined as:

[0055]

[0056] Where d(·) represents the differential; D L (ω) represents the logarithmic derivative.

[0057] In actual implementation, the system admittance matrix can be modeled as a discretized frequency domain model, so the logarithmic derivative D can be realized by differential approximation. L Calculation of (ω).

[0058] Optionally, in one embodiment of the present application, the calculation formula of the logarithmic derivative is:

[0059]

[0060] Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

[0061] In step S102 , the real part extreme value point of the logarithmic derivative and its adjacent frequency points are obtained, and the dominant oscillation mode of the power system is pre-identified based on the real part extreme value point and its adjacent frequency points.

[0062] Among them, the dominant oscillation mode refers to the mode that has the most significant impact on the dynamic behavior of the system and requires the most intensive monitoring and control among the various oscillation modes of the power system. It usually has the lowest damping ratio or the maximum energy participation.

[0063] Optionally, in one embodiment of the present application, the dominant oscillation mode of the power system is pre-identified based on the real part extreme point and its adjacent frequency points, including: extracting the real part-frequency characteristic curve and the imaginary part-frequency characteristic curve of the logarithmic derivative to obtain the real part and the imaginary part, and determining the candidate frequency point of the dominant oscillation mode; calculating the imaginary part slope of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point based on the real part, the imaginary part, and the candidate frequency point; and determining the dominant oscillation mode based on the real part and the imaginary part slope of the logarithmic derivative.

[0064] It should be noted that the zeros of the admittance matrix determinant G(ω) correspond to the oscillation modes of the power system.

[0065] Specifically, the embodiment of the present application can be realized by the logarithmic derivative D L The frequency characteristic curve of (ω) can be used to pre-identify the dominant oscillation mode, which can include the following steps:

[0066] (1) The embodiment of the present application first extracts the logarithmic derivative D L The real part and imaginary part of (ω) are respectively denoted as Re(D L (ω)) and Im(D L (ω)). In the embodiment of the present application, if a frequency ω a Department, Re (D L (ω a )) is a local extreme value (maximum or minimum), then the frequency point is determined to be a candidate frequency point of the dominant oscillation mode.

[0067] (2) Furthermore, in the embodiment of the present application, at the candidate frequency point ω a At this point, its relationship with the adjacent frequency points (ω a -Δω、ω a +Δω) between the imaginary part of the logarithmic derivative slope k x1 and k x2 , which can be expressed as:

[0068]

[0069] (3) In some cases, in the embodiments of the present application, if the real part of the logarithmic derivative satisfies |Re(D L (ω a -Δω))|≤|Re(D L (ω a +Δω))|, if ω a With ω a The imaginary slope between +Δω satisfies k x2 <0, it can be determined that the candidate frequency point corresponds to a dominant zero point of the determinant of the admittance matrix (i.e., the dominant oscillation mode of the power system); if ω a With ω a The imaginary slope between +Δω satisfies k x2 >0, it may correspond to a dominant pole of the determinant of the admittance matrix.

[0070] Furthermore, if the real part of the logarithmic derivative satisfies |Re(D L (ω a -Δω))|>|Re(D L (ω a+Δω))|, if ω a -Δω and ω a The imaginary slope between satisfies k x1 <0, it can be determined that the candidate frequency point corresponds to a dominant zero point of the determinant of the admittance matrix (i.e., the dominant oscillation mode of the power system); if ω a -Δω and ω a The imaginary slope between satisfies k x1 >0, it may correspond to a dominant pole of the determinant of the admittance matrix.

[0071] In step S103 , the oscillation damping and frequency of the power system are calculated according to the dominant oscillation mode.

[0072] It is understandable that in power systems, oscillation damping and frequency are key parameters that characterize the dynamic response characteristics of the system. The oscillation frequency indicates how fast the system generates periodic oscillations after being disturbed, usually in Hertz (Hz); the oscillation damping reflects the speed at which the oscillation energy decays, and its magnitude directly affects whether the oscillation can decay quickly or continue to amplify. The smaller the damping ratio, the slower the oscillation decays, and the more likely the system is to experience sustained oscillations or instability. Therefore, identifying the frequency and damping characteristics of the dominant oscillation mode can accurately assess the dynamic stability margin of the system, promptly detect potential oscillation risks, and provide a basis for parameter adjustment of the damping controller, thereby improving the oscillation suppression capability and overall operational stability of the power system under disturbances.

[0073] Optionally, in one embodiment of the present application, the oscillation damping and frequency of the power system are calculated according to the dominant oscillation mode, including: within the dominant mode frequency neighborhood, selecting the real and imaginary data of the logarithmic derivatives of the candidate frequency points and the adjacent frequency points to fit using a preset fitting formula to solve the oscillation damping and frequency.

[0074] The calculation of oscillation damping and frequency is described below using a specific example. The embodiment of the present application may include the following steps:

[0075] (1) In the embodiment of the present application, it is assumed that the candidate frequency point ω a Corresponding to the dominant zero z = α i +jω i , then in ω a In the neighborhood, the real and imaginary parts of the logarithmic derivative can satisfy the following theoretical analytical relationship:

[0076]

[0077] (2) In the dominant mode frequency neighborhood, the embodiment of the present application can select a candidate frequency point ω a and its left and right adjacent frequency points ω a -Δω and ω aThe real and imaginary data of the logarithmic derivative at +Δω can be used to solve the unknown parameter α in the equation and by curve fitting technology. i and ω i .

[0078] Optionally, in one embodiment of the present application, the fitting formula can be expressed as:

[0079]

[0080] stω∈{ω a -Δω,ω a ,ω a +Δω}

[0081] Among them, w Re 、w Im Represents the weight coefficient of the real and imaginary parts of the logarithmic derivative, which can be set according to actual needs; ω a Indicates candidate frequency points; α i 、ω i They represent the damping and frequency of the i-th dominant zero / pole of the system respectively.

[0082] In the actual execution process, in order to improve the convergence of the optimization, the embodiment of the present application can set the initial value of the parameter α i0 and jω i0 The initial value can be solved by the following equations:

[0083]

[0084] In the examples of this application, it can be concluded that:

[0085]

[0086] ω i0 =ω a -α i0 ·k a ,

[0087] Among them, k a =Im(D L (ω a )) / Re(D L (ω a )).

[0088] According to the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system proposed in the embodiment of the present application, the dominant oscillation mode of the power system is pre-identified by the extreme point of the real part of the logarithmic derivative and its adjacent frequency points, and then the oscillation damping and frequency of the power system are calculated. Under the premise of considering the frequency step, the logarithmic derivative can be improved based on the determinant of the admittance matrix to achieve accurate identification of the dominant oscillation mode, quantitatively obtain key parameters such as oscillation damping and frequency, and improve the sensitivity and accuracy of oscillation mode identification, thereby providing technical support for the analysis and prevention of broadband oscillations in the power system.

[0089] Next, a logarithmic derivative quantitative analysis device for a dominant oscillation mode of a power system proposed in an embodiment of the present application will be described with reference to the accompanying drawings.

[0090] Figure 2 4 is a block diagram of a device for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of a power system according to an embodiment of the present application.

[0091] like Figure 2 As shown, the logarithmic derivative quantitative analysis device 10 of the dominant oscillation mode of the power system includes: an acquisition module 100 , an identification module 200 and an analysis module 300 .

[0092] The acquisition module 100 is used to determine the frequency step of the power system and obtain the logarithmic derivative of the determinant of the admittance matrix according to the frequency step.

[0093] The identification module 200 is used to obtain the real part extreme value point and its adjacent frequency points of the logarithmic derivative, and pre-identify the dominant oscillation mode of the power system based on the real part extreme value point and its adjacent frequency points.

[0094] The analysis module 300 is configured to calculate the oscillation damping and frequency of the power system according to the dominant oscillation mode.

[0095] Optionally, in one embodiment of the present application, the calculation formula of the logarithmic derivative is:

[0096]

[0097] Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

[0098] Optionally, in one embodiment of the present application, the identification module 200 includes: a determination unit, a calculation unit, and a judgment unit.

[0099] The determination unit is used to extract the real part-frequency characteristic curve and the imaginary part-frequency characteristic curve of the logarithmic derivative to obtain the real part and the imaginary part, and determine the candidate frequency point of the dominant oscillation mode.

[0100] The calculation unit is used to calculate the imaginary part slope of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point based on the real part, the imaginary part, and the candidate frequency point.

[0101] The judging unit is used to judge the dominant oscillation mode according to the slopes of the real part and the imaginary part of the logarithmic derivative.

[0102] Optionally, in one embodiment of the present application, the analysis module includes: a solution unit.

[0103] The solving unit is used to select the real and imaginary data of the logarithmic derivatives of the candidate frequency points and adjacent frequency points in the dominant mode frequency neighborhood to fit the data using a preset fitting formula to solve the oscillation damping and frequency.

[0104] Optionally, in one embodiment of the present application, the fitting formula is:

[0105]

[0106] stω∈{ω a -Δω,ω a ,ω a +Δω}

[0107] Among them, w Re 、w Im Represents the weight coefficient of the real and imaginary parts of the logarithmic derivative; ω a Indicates candidate frequency points; α i 、ω i They represent the damping and frequency of the i-th dominant zero / pole of the system respectively.

[0108] It should be noted that the above explanation of the embodiment of the method for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of the power system is also applicable to the device for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of the power system of this embodiment, and will not be repeated here.

[0109] According to the logarithmic derivative quantitative analysis device of the dominant oscillation mode of the power system proposed in the embodiment of the present application, the dominant oscillation mode of the power system is pre-identified by the extreme point of the real part of the logarithmic derivative and its adjacent frequency points, and then the oscillation damping and frequency of the power system are calculated. Under the premise of considering the frequency step, the logarithmic derivative can be improved based on the determinant of the admittance matrix to achieve accurate identification of the dominant oscillation mode, quantitatively obtain key parameters such as oscillation damping and frequency, and improve the sensitivity and accuracy of oscillation mode identification, thereby providing technical support for the analysis and prevention of broadband oscillations in the power system.

[0110] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0111] Memory 301 , processor 302 , and computer programs stored in the memory 301 and executable on the processor 302 .

[0112] When the processor 302 executes the program, the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system provided in the above embodiment is implemented.

[0113] Furthermore, the electronic device further includes:

[0114] The communication interface 303 is used for communication between the memory 301 and the processor 302 .

[0115] The memory 301 is used to store computer programs that can be run on the processor 302 .

[0116] The memory 301 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0117] If the memory 301, processor 302, and communication interface 303 are implemented independently, the communication interface 303, memory 301, and processor 302 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0118] Optionally, in a specific implementation, if the memory 301 , the processor 302 and the communication interface 303 are integrated on a chip, the memory 301 , the processor 302 and the communication interface 303 can communicate with each other through an internal interface.

[0119] The processor 302 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0120] This embodiment further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the above-mentioned logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system is implemented.

[0121] An embodiment of the present application also provides a computer program product, including a computer program, which can run computer instructions. When the computer instructions are executed by a processor, the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system provided in the embodiment of the present application is implemented.

[0122] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0123] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0124] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0125] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0126] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented using hardware, as in another embodiment, it can be implemented using any one or a combination of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0127] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0128] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0129] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A logarithmic derivative quantitative analysis method for the dominant oscillation mode of a power system, characterized by: The following steps are involved: determining a frequency step size of the power system, and obtaining a logarithmic derivative of a determinant of an admittance matrix according to the frequency step size; Obtaining a real part extreme value point and an adjacent frequency point of the logarithmic derivative, and pre-identifying a dominant oscillation mode of the power system based on the real part extreme value point and the adjacent frequency point; Oscillation damping and frequency of the power system are calculated based on the dominant oscillation mode.

2. The method according to claim 1, characterized in that The calculation formula of the logarithmic derivative is: Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

3. The method according to claim 1, characterized in that The pre-identifying the dominant oscillation mode of the power system according to the real part extreme point and its adjacent frequency points includes: Extracting the real part-frequency characteristic curve and the imaginary part-frequency characteristic curve of the logarithmic derivative to obtain the real part and the imaginary part, and determining the candidate frequency point of the dominant oscillation mode; Calculate the imaginary part slope of the logarithmic derivative between adjacent frequency points adjacent to the candidate frequency point based on the real part, the imaginary part, and the candidate frequency point; The dominant oscillation mode is determined based on the slopes of the real part and the imaginary part of the logarithmic derivative.

4. The method according to claim 3, characterized in that The calculating the oscillation damping and frequency of the power system according to the dominant oscillation mode includes: In the dominant mode frequency neighborhood, real and imaginary data of logarithmic derivatives of the candidate frequency points and the adjacent frequency points are selected to perform fitting using a preset fitting formula to solve the oscillation damping and frequency.

5. The method according to claim 4, characterized in that The fitting formula is: stω∈{ω a -Look, oh a ,oh a +See} Among them, w Re 、w Im Represents the weight coefficient of the real and imaginary parts of the logarithmic derivative; ω a Indicates candidate frequency points; α i 、ω i They represent the damping and frequency of the i-th dominant zero / pole of the system respectively.

6. A device for quantitatively analyzing the logarithmic derivative of the dominant oscillation mode of a power system, characterized in that: include: an acquisition module, configured to determine a frequency step of the power system and acquire a logarithmic derivative of the determinant of the admittance matrix according to the frequency step; an identification module, configured to obtain a real extreme point of the logarithmic derivative and its adjacent frequency points, and pre-identify a dominant oscillation mode of the power system based on the real extreme point and its adjacent frequency points; An analysis module is configured to calculate the oscillation damping and frequency of the power system according to the dominant oscillation mode.

7. The device according to claim 6, characterized in that The calculation formula of the logarithmic derivative is: Among them, D L (ω) represents the logarithmic derivative; G(ω) expresses the determinant of the admittance matrix; ω represents the angular frequency; Δω represents the selected frequency step.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system according to any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system as claimed in any one of claims 1 to 5.

10. A computer program product comprising a computer program, characterized in that The computer program is executed to implement the logarithmic derivative quantitative analysis method of the dominant oscillation mode of the power system according to any one of claims 1 to 5.

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