High-proportion wind power access system broadband oscillation suppression method based on impedance shaping

Abstract

The invention relates to the technical field of stability control of a power system, in particular to a broadband oscillation suppression method for a high-proportion wind power access system based on impedance shaping. The method comprises the following steps: constructing a frequency domain output impedance matrix, extracting a dominant broadband oscillation coupling mode frequency band, introducing an impedance shaping compensation mechanism driven by modal suppression, constructing a modal suppression driving quantity based on a modal direction in a dominant broadband oscillation coupling mode, and carrying out impedance local shaping on output impedance; and on the basis of the modal suppression driving quantity, quantifying the modal interference sensitivity between the wind power converters, and introducing an impedance shaping gain correction mechanism based on the modal interference sensitivity to correct the target output impedance after local shaping. The problems of undifferentiated shaping and excessive compensation caused by the fact that dynamic adjustment cannot be effectively carried out according to the equipment capability and the frequency risk of the wind power converter in the shaping process are solved; interference coupling between the wind power converters cannot be effectively suppressed, and excessive oscillation or suppression is generated.

Description

Technical Field

[0001] This invention relates to the field of power system stability control technology, and in particular to a broadband oscillation suppression method for high-proportion wind power integrated systems based on impedance shaping. Background Technology

[0002] With the rapid development of renewable energy, a large number of new energy sources such as wind power have been connected to the grid, which has led to changes in the system impedance structure. The stability support capability that traditionally relies on the inertia of synchronous generators has gradually weakened. Especially in areas with a high proportion of wind power connected to the grid, wind farms are connected to the grid through power electronic converters, which changes the equivalent impedance characteristics of the system. In the mid-to-high frequency range, broadband oscillations are easily induced, affecting system stability and power quality.

[0003] To ensure the stability and efficient operation of the wind power grid, the output impedance shaping of wind power converters is crucial for improving system performance. In the prior art, wind power converters optimize their output characteristics through modal analysis and impedance shaping methods. Although these methods can improve system stability to some extent, they often have the following problems: (1) Indiscriminate shaping and overcompensation: During the shaping process, dynamic adjustments are not effectively made according to the equipment capacity and frequency risk of each wind power converter, resulting in indiscriminate shaping and overcompensation, which affects the overall stability of the system; (2) Interference coupling problem: Interference coupling between wind power converters is not effectively suppressed, which may lead to unreasonable modal interference amplification, excessive oscillation or suppression, and affect the frequency response of the system.

[0004] Therefore, in order to address the above shortcomings, there is an urgent need to provide a broadband oscillation suppression method for high-proportion wind power access systems based on impedance shaping. Summary of the Invention

[0005] This invention provides a broadband oscillation suppression method for high-proportion wind power access systems based on impedance shaping. This method addresses the problems of ineffective dynamic adjustment based on the equipment capacity and frequency risk of each wind power converter during the shaping process, which leads to indiscriminate shaping and overcompensation, affecting the overall stability of the system; and the failure to effectively suppress interference coupling between wind power converters, which may result in unreasonable modal interference amplification, excessive oscillation, or suppression, affecting the frequency response of the system.

[0006] The present invention provides a method for suppressing broadband oscillations in high-proportion wind power grid systems based on impedance shaping, comprising the following steps: S1. Collect the output impedance at each frequency sampling point and construct a frequency domain output impedance matrix; based on the frequency domain output impedance matrix, extract the frequency band of the dominant broadband oscillation coupling mode and obtain the mode direction and mode contribution of the dominant broadband oscillation coupling mode; introduce a mode suppression driven impedance shaping compensation mechanism, construct the mode suppression driving quantity based on the mode direction in the dominant broadband oscillation coupling mode, and perform local impedance shaping on the output impedance to obtain the target output impedance after local shaping; S2. Based on the modal suppression driving quantity, the modal interference sensitivity between wind power converters is quantified, and an impedance shaping gain correction mechanism based on the modal interference sensitivity is introduced to correct the target output impedance after local shaping, so as to obtain the final output impedance after global shaping.

[0007] Preferably, S1 specifically includes: The frequency domain output impedance matrix is ​​decomposed using the singular value decomposition method. The maximum singular value is selected and normalized to construct a normalized maximum singular value sequence.

[0008] Preferably, S1 specifically includes: Based on the normalized maximum singular value sequence and a preset threshold, the dominant broadband oscillation coupling mode frequency band is extracted. Based on the frequency sampling points covered within the dominant broadband oscillation coupling mode frequency band, a frequency sampling point subset is constructed, the dominant broadband oscillation coupling mode direction under the frequency sampling points is extracted, and the mode contribution is obtained.

[0009] Preferably, S1 specifically includes: In the implementation of the impedance shaping compensation mechanism driven by mode suppression, the modal contribution normalization factor is calculated based on the direction of the dominant broadband oscillation coupled mode. Combined with the frequency risk weight, and the controller shaping capability factor is introduced to construct the mode suppression driving quantity; the frequency risk weight is calculated based on the maximum singular value.

[0010] Preferably, S1 specifically includes: The modal suppression driving force is applied to the modal contribution, and the output impedance in the frequency domain output impedance matrix is ​​locally shaped to obtain the target output impedance after local shaping.

[0011] Preferably, S2 specifically includes: In the implementation of the impedance shaping gain correction mechanism based on modal interference sensitivity, the modal interference influence coefficient between different wind power converters is quantified based on the modal contribution, and the modal interference sensitivity is obtained by combining the modal suppression driving quantity.

[0012] Preferably, S2 specifically includes: In the implementation of the impedance shaping gain correction mechanism based on modal interference sensitivity, the modal interference sensitivity is summed and averaged to calculate the shaping gain correction factor.

[0013] Preferably, S2 specifically includes: In the implementation of the impedance shaping gain correction mechanism based on modal interference sensitivity, the impedance shaping adjustment amount is obtained based on the shaping gain correction factor, the modal suppression driving amount and the modal contribution. Based on the impedance shaping adjustment amount, the target output impedance after local shaping is corrected to obtain the final output impedance after global shaping.

[0014] The beneficial effects of the technical solution of the present invention are: 1. This invention proposes an impedance shaping compensation mechanism driven by mode suppression, which can accurately guide the shaping direction to align with the dominant broadband oscillation coupling mode. It can also adjust the shaping intensity according to the wind power converter equipment capacity and the risk level of the frequency sampling point, effectively avoiding the problems of indiscriminate shaping and overcompensation, and realizing local shaping.

[0015] 2. This invention proposes an impedance shaping gain correction mechanism based on modal interference sensitivity, which not only considers the modal response capability of each wind power converter, but also the modal interference sensitivity between wind power converters, reduces unreasonable interference coupling, avoids the risk of excessive oscillation or excessive suppression, and ensures the safe and stable operation of a high proportion of wind power connected to the system. Attached Figure Description

[0016] Figure 1 This is a flowchart of the broadband oscillation suppression method for high-proportion wind power access systems based on impedance shaping, as described in this invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The following description, in conjunction with the accompanying drawings, details the specific scheme of the broadband oscillation suppression method for high-proportion wind power access systems based on impedance shaping provided by this invention.

[0020] See attached document Figure 1The diagram illustrates a flowchart of a broadband oscillation suppression method for high-proportion wind power grid integration systems based on impedance shaping, according to an embodiment of the present invention. The method includes the following steps: S1. Collect the output impedance at each frequency sampling point and construct a frequency domain output impedance matrix; based on the frequency domain output impedance matrix, extract the frequency band of the dominant broadband oscillation coupling mode and obtain the mode direction and mode contribution of the dominant broadband oscillation coupling mode; introduce a mode suppression driven impedance shaping compensation mechanism, construct the mode suppression driving quantity based on the mode direction in the dominant broadband oscillation coupling mode, and perform local impedance shaping on the output impedance to obtain the target output impedance after local shaping; Wind power grid connection system is The typhoon power converter consists of multiple wind turbines, each operating at a specific frequency. The output impedance behavior under these conditions is denoted as a function. ,in, Indicates the index of the wind power converter. To characterize the wind power converter in the entire wind power grid system in the frequency band The coupling relationship within is selected at equal intervals. Each frequency sampling point constitutes a frequency set. Among them, frequency band The settings can be made based on the frequency sampling points corresponding to the historical output impedance in the existing wind power converter database. and These represent the lower and upper limits of the frequency band, respectively. Indicates the index of the frequency sampling point. ; at each frequency sampling point At this point, a frequency domain output impedance matrix is ​​constructed at the wind power grid connection system level. The diagonal elements of the frequency domain output impedance matrix For the first Typhoon power converter at frequency sampling point Output impedance at off-diagonal element For the first Typhoon power converter and the first Typhoon power converter at frequency sampling point The coupling impedance at the point, .

[0021] Furthermore, based on the frequency domain output impedance matrix, the dominant broadband oscillation coupling mode frequency band is determined: using existing singular value decomposition methods, the frequency domain output impedance matrix is ​​analyzed. Perform singular value decomposition and select the largest singular value. And sample the maximum singular value by frequency point The values ​​are sorted from smallest to largest to generate the frequency response curve with the largest singular value. The frequency sampling points are then calculated. Maximum singular value at The ratio of the maximum value of the largest singular value among all frequency sampling points to the maximum value of the largest singular value yields the normalized maximum singular value sequence. Based on the normalized maximum singular value sequence, a threshold is set using the existing mean deviation method. Frequency sampling points in the normalized maximum singular value sequence that are greater than the threshold are aggregated according to their frequency sampling point values ​​to identify one or more sets of continuous frequency sampling point intervals. The closed interval between the minimum and maximum frequency sampling points in each set is taken as the dominant broadband oscillation coupling mode frequency band. Subsequently, the frequency sampling points covered within the dominant broadband oscillation coupling mode frequency band are collected to form a frequency sampling point subset. ,in, This indicates the index of the frequency sampling point within the frequency band of the dominant broadband oscillation coupling mode. , This represents the number of frequency sampling points within the dominant broadband oscillation coupling mode band, and represents a subset of frequency sampling points. Each frequency sampling point The corresponding maximum singular value The corresponding left singular vector As frequency sampling point The dominant broadband oscillatory coupled mode direction at the location, where each left singular vector component Indicates at frequency sampling point In the dominant broadband oscillation coupled mode at the location of the first Modal contribution of the typhoon power converter, the It is a complex value, where the amplitude represents the modal contribution modulus and the phase angle reflects the response phase.

[0022] After extracting the frequency band of the dominant broadband oscillation coupling mode of the wind power grid and the mode direction and mode contribution of each wind power converter in the dominant broadband oscillation coupling mode, the impedance local shaping stage is entered: a mode suppression driven impedance shaping compensation mechanism is proposed. Based on the dominant broadband oscillation coupling mode direction, a mode suppression driving quantity is constructed, consisting of a mode contribution normalization factor, a controller shaping capability factor, and a frequency risk weight. The mode suppression driving quantity is applied to the mode contribution in a multiplicative structure, thereby achieving directional weakening of the output impedance in the dominant broadband oscillation coupling mode direction, and obtaining the target output impedance after local shaping, as shown in the following formula: , in, For the first time after local plastic surgery Typhoon power converter at frequency sampling point The target output impedance at that point is the target output impedance under ideal conditions; For the first Typhoon power converter at frequency sampling point Output impedance at; For the first Typhoon power converter at frequency sampling point The modal suppression driving force at a given point is obtained by multiplying the modal contribution normalization factor, the controller shaping capability factor, and the frequency risk weight; , indicating the first Typhoon power converter at frequency sampling point Modal contribution normalization factor at the location, where Indicates the first Typhoon power converter at frequency sampling point The modal contribution of the dominant broadband oscillation coupling mode at a given location can indicate the direction of shaping. The amplitude represents the modal contribution modulus. , indicating the first The controller shaping capability factor of the typhoon power converter is obtained through the existing wind power converter database; , where is the frequency risk weight, representing the frequency sampling point The relative risk level of the frequency in the dominant broadband oscillation coupling mode is determined by the frequency risk weight. The larger the frequency risk weight, the greater the risk of the frequency sampling point, and the more the shaping intensity should be increased. For frequency sampling points At that point, the maximum singular value of the frequency domain output impedance matrix; It is a subset of frequency sampling points within the dominant broadband oscillation coupling mode frequency band.

[0023] The above formula proposes a mode suppression-driven impedance shaping compensation mechanism, which can accurately guide the shaping direction to align with the dominant broadband oscillation coupling mode. It can also adjust the shaping intensity according to the wind power converter equipment capacity and the risk level of the frequency sampling point, effectively avoiding the problems of indiscriminate shaping and overcompensation, and realizing local shaping.

[0024] S2. Based on the modal suppression driving quantity, the modal interference sensitivity between wind power converters is quantified, and an impedance shaping gain correction mechanism based on the modal interference sensitivity is introduced to correct the target output impedance after local shaping, so as to obtain the final output impedance after global shaping.

[0025] Furthermore, to achieve global coordinated impedance shaping of wind power converters in wind power grid systems, an impedance shaping gain correction mechanism based on modal interference sensitivity is proposed. This mechanism is achieved by calculating the first... The shaping behavior of the typhoon power converter on the first The modal interference influence coefficient of the typhoon power converter, combined with the first The modal suppression drive of the typhoon power converter is obtained. Typhoon power converter for the first The modal disturbance sensitivity of the typhoon power converter is calculated by summing and averaging the modal disturbance sensitivities to obtain the global average modal disturbance sensitivity. Finally, it is... The way to obtain the first Typhoon power converter at frequency sampling point The shaping gain correction factor at the specified location is calculated using the following formula: , in, For the first Typhoon power converter at frequency sampling point The shaping gain correction factor at the location; For the number of wind power converters, In addition to the first The number of wind power converters other than those used in typhoon power converters; For the first The shaping behavior of the typhoon power converter on the first The modal interference influence coefficient of the typhoon power converter can reflect the first... The shaping behavior of the typhoon power converter on the first Typhoon power converter at frequency sampling point The degree of influence in the direction of the dominant broadband oscillation coupling mode: If the value of the modal interference influence coefficient is positive, it indicates that the first... Shaping behavior of typhoon power converter and the first The dominant broadband oscillation coupling modes of the typhoon power converter are aligned, resulting in a coupling enhancement effect that amplifies the overall broadband oscillation response of the wind power grid. Therefore, coordinated impedance shaping is necessary. If the modal interference influence coefficient is negative, it indicates that the... Shaping behavior of typhoon power converter and the first The dominant broadband oscillation coupling modes of the typhoon power converter are in opposite directions, and there is an interference suppression effect between them, which will reduce the global broadband oscillation response of the wind power grid. This is used to ensure that the shaping gain adjustment is only included when the dominant broadband oscillation coupling modes of the two wind power converters are in the same direction; This indicates the operation of taking the real part; Indicates the first Typhoon power converter at frequency sampling point Modal contribution in the direction of the dominant broadband oscillation coupling mode. Indicates conjugate transpose; Indicates the first Typhoon power converter at frequency sampling point Modal contribution in the direction of the dominant broadband oscillation coupling mode; Indicates the first Typhoon power converter for the first Modal interference sensitivity of typhoon power converter; For the first Typhoon power converter at frequency sampling point Modal suppression driving quantity at the location.

[0026] The above formula proposes an impedance shaping gain correction mechanism based on modal interference sensitivity. It not only considers the modal response capability of each wind power converter, but also the modal interference sensitivity between wind power converters. This can reduce unreasonable interference coupling, thereby avoiding the risk of excessive oscillation or excessive suppression and ensuring the safe and stable operation of a high proportion of wind power connected to the system.

[0027] Ultimately, by passing the first Typhoon power converter at frequency sampling point The shaping gain correction factor at a given point is multiplied by the mode suppression drive and the mode contribution to obtain the impedance shaping adjustment. Based on the impedance shaping adjustment, the target output impedance after local shaping is corrected to obtain the final output impedance after global shaping, as shown in the following formula: , in, For the first time after global reshaping Typhoon power converter at frequency sampling point The final output impedance at the point; For the first time after local plastic surgery Typhoon power converter at frequency sampling point The target output impedance at that point is the target output impedance under ideal conditions; Indicates the first Typhoon power converter at frequency sampling point Impedance shaping adjustment amount at the location; For the first Typhoon power converter at frequency sampling point The shaping gain correction factor at the location; For the first Typhoon power converter at frequency sampling point Modal suppression driving quantity at the location; Indicates the first Typhoon power converter at frequency sampling point Modal contribution in the direction of the dominant broadband oscillation coupling mode.

[0028] In summary, a broadband oscillation suppression method for high-proportion wind power grid systems based on impedance shaping has been developed.

[0029] The order of the embodiments is for illustrative purposes only and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0030] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for suppressing wideband oscillation in a high-penetration wind power integrated system based on impedance shaping, characterized in that, The method comprises the following steps: S1. Collecting the output impedance at each frequency sampling point and constructing a frequency domain output impedance matrix; based on the frequency domain output impedance matrix, extracting a dominant broadband oscillation coupling modal frequency band and obtaining a modal direction and a modal contribution degree of the dominant broadband oscillation coupling modal; introducing an impedance shaping compensation mechanism of modal suppression driving, constructing a modal suppression driving quantity based on the modal direction in the dominant broadband oscillation coupling modal, and locally shaping the output impedance to obtain a target output impedance after local shaping; S2. Quantifying the modal interference sensitivity between wind power converters based on the modal suppression driving quantity, and introducing an impedance shaping gain correction mechanism based on the modal interference sensitivity to correct the target output impedance after local shaping to obtain a final output impedance after global shaping.

2. The impedance shaping based high renewable penetration power system wideband oscillation suppression method of claim 1, wherein, The S1 specifically comprises: The frequency domain output impedance matrix is singular value decomposed by a singular value decomposition method, the maximum singular value is selected and normalized to construct a normalized maximum singular value sequence.

3. The impedance shaping based high renewable penetration power system wideband oscillation suppression method of claim 2, wherein, The S1 specifically comprises: Based on the normalized maximum singular value sequence, the dominant broadband oscillation coupling modal frequency band is extracted in combination with a preset threshold; a frequency sampling point sub-set is constructed based on the frequency sampling points covered in the dominant broadband oscillation coupling modal frequency band, the dominant broadband oscillation coupling modal direction under the frequency sampling points is extracted, and the modal contribution degree is obtained.

4. The impedance shaping based high renewable penetration power system wideband oscillation suppression method of claim 3, wherein, The S1 specifically comprises: In the implementation process of the impedance shaping compensation mechanism of modal suppression driving, the modal contribution degree normalization factor is calculated based on the dominant broadband oscillation coupling modal direction, the frequency risk weight is combined, and the controller shaping capability factor is introduced to construct the modal suppression driving quantity; the frequency risk weight is calculated based on the maximum singular value.

5. The impedance shaping based high renewable penetration power system wideband oscillation damping method according to claim 4, wherein, The S1 specifically comprises: The modal suppression driving quantity is applied to the modal contribution degree to locally shape the output impedance in the frequency domain output impedance matrix to obtain the target output impedance after local shaping.

6. The impedance-shaping-based high-penetration wind power integration system wide-area oscillation suppression method according to claim 1, characterized in that, The S2 specifically comprises: In the implementation process of the impedance shaping gain correction mechanism based on the modal interference sensitivity, the modal interference influence coefficient between the shaping behaviors of different wind power converters is quantified based on the modal contribution degree, and the modal interference sensitivity is obtained in combination with the modal suppression driving quantity.

7. The impedance shaping based high renewable penetration power system wideband oscillation damping method according to claim 6, wherein, The S2 specifically comprises: In the implementation process of the impedance shaping gain correction mechanism based on the modal interference sensitivity, the modal interference sensitivity is summed and averaged to calculate a shaping gain correction factor.

8. The impedance shaping based high renewable penetration power system wideband oscillation suppression method of claim 7, wherein, The S2 specifically comprises: In the implementation process of the impedance shaping gain correction mechanism based on the modal interference sensitivity, the impedance shaping adjustment quantity is obtained based on the shaping gain correction factor, the modal suppression driving quantity and the modal contribution degree; based on the impedance shaping adjustment quantity, the target output impedance after local shaping is corrected to obtain the final output impedance after global shaping.

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