A method, device and medium for suppressing subsynchronous oscillation caused by new energy grid connection

Abstract

The present invention discloses a method, device and medium for suppressing subsynchronous oscillation caused by the grid connection of new energy, which is applicable to the field of subsynchronous oscillation. When it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than the current threshold, a double-tuned filter is put into use and the current oscillation frequency is obtained; the current oscillation frequency is input into the double-tuned filter to obtain a first inductance value and a second inductance value; when the first inductance value and the second inductance value meet the preset conditions, they are adjusted to complete the suppression of subsynchronous oscillation. The subsynchronous component and supersynchronous component generated by the subsynchronous oscillation caused by the grid connection of new energy are suppressed by a determined double-tuned filter. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch, and then the first inductance value and the second inductance value are obtained. When the preset conditions are met, the first inductance value and the second inductance value are adjusted to suppress the subsynchronous oscillation caused by the grid connection of new energy, thereby improving the operating reliability of the wind turbines in the wind farm.

Description

Technical Field

[0001] The present invention relates to the field of subsynchronous oscillation, and in particular to a method, device and medium for suppressing subsynchronous oscillation caused by grid connection of new energy. Background Art

[0002] Subsynchronous oscillations (SSOs) are a key stability issue in power systems. Due to their complexity and severe potential harm to power systems, they have attracted significant attention from power producers and researchers. With the increasing integration of wind power into the grid, there have been numerous incidents of wind farm disconnections and localized grid decoupling caused by SSOs.

[0003] Currently, there are different classifications of subsynchronous oscillations caused by renewable energy grid integration. Subsynchronous oscillations caused by renewable energy grid integration occur in areas with weak grid conditions and high wind power capacity. Existing subsynchronous oscillations caused by renewable energy grid integration are mostly due to series capacitor compensation. There are no mature solutions to suppress subsynchronous oscillations caused by renewable energy grid integration without series compensation. Therefore, these solutions are unable to meet the needs of such scenarios and have certain limitations in suppressing subsynchronous oscillations.

[0004] Therefore, it is urgent for those skilled in the art to find a method to suppress subsynchronous oscillation caused by grid-connected renewable energy without series compensation. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, device and medium for suppressing subsynchronous oscillation caused by grid connection of renewable energy, so as to meet the subsynchronous oscillation suppression scenario caused by grid connection of renewable energy without series compensation, and improve the operating reliability of wind turbines in wind farms.

[0006] To solve the above technical problems, the present invention provides a method for suppressing subsynchronous oscillation caused by renewable energy grid connection, comprising:

[0007] When it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than the current threshold, the double-tuned filter is activated and the current oscillation frequency of the current outgoing current of the wind farm is obtained, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch;

[0008] Inputting the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch;

[0009] When the first inductance value and the second inductance value meet a preset condition, adjustments are made to suppress subsynchronous oscillation.

[0010] Preferably, the parameters of the double-tuned filter are obtained by:

[0011] Obtain the voltage data and reactive power of the wind farm to obtain the short-circuit capacity of the grid when the wind farm is connected to the grid;

[0012] Determine a first equivalent impedance value of the subsynchronous filter branch and a second equivalent impedance value of the supersynchronous filter branch according to the relationship between the short-circuit capacity, the rated voltage value, the current oscillation frequency and the rated frequency;

[0013] Determining a first reactance parameter and a first capacitance parameter corresponding to the sub-synchronous filter branch according to the first equivalent impedance value and the factor number of the sub-synchronous filter branch;

[0014] The second reactance parameter and the second capacitance parameter corresponding to the super synchronous filter branch are determined according to the second equivalent impedance and the factor number of the super synchronous filter branch to obtain the parameters of the double tuned filter.

[0015] Preferably, the preset condition is that the first inductance value is within a first preset inductance value range and the second inductance value is within a second preset inductance value range;

[0016] The minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by at least one of three methods: the operation mode of the power grid, the subsynchronous oscillation frequency, and the capacitance values ​​corresponding to different branches of the double-tuned filter.

[0017] Preferably, the minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by the operation mode of the power grid, specifically as follows:

[0018] Obtain the maximum short-circuit capacity and the minimum short-circuit capacity among the short-circuit capacities;

[0019] Determine the minimum fundamental short-circuit impedance based on the maximum short-circuit capacity and rated voltage value;

[0020] Determine the maximum fundamental short-circuit impedance based on the minimum short-circuit capacity and rated voltage;

[0021] The minimum first inductance value and the minimum second inductance value under the minimum operation mode of the power grid and the maximum first inductance value and the maximum second inductance value under the maximum operation mode of the power grid are determined according to the maximum fundamental short-circuit impedance and the minimum fundamental short-circuit impedance, and the first reactance parameter and the second reactance parameter.

[0022] Preferably, the minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by a subsynchronous oscillation frequency method, which is specifically as follows:

[0023] Obtain the minimum oscillation frequency and the maximum oscillation frequency among the oscillation frequencies;

[0024] The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the minimum oscillation frequency, the maximum oscillation frequency, the first reactance parameter, and the second reactance parameter.

[0025] Preferably, the minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by means of capacitance values ​​corresponding to different branches of the double-tuned filter, which are specifically as follows:

[0026] Get the rated capacitance value and the maximum capacitance value of the capacitor;

[0027] The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the rated capacitance value, the maximum capacitance value, the first reactance parameter, and the second reactance parameter.

[0028] Preferably, the current oscillation frequency includes a subsynchronous oscillation frequency and a supersynchronous oscillation frequency, and determining a first equivalent impedance value of the subsynchronous filter branch and a second equivalent impedance value of the supersynchronous filter branch according to the relationship between the short-circuit capacity, the rated voltage value, the current oscillation frequency, and the rated frequency includes:

[0029] Determine the fundamental short-circuit impedance value based on the relationship between the short-circuit capacity and the rated voltage value;

[0030] Determine a first impedance value at a subsynchronous oscillation frequency and a second impedance value at a supersynchronous oscillation frequency according to the fundamental wave short-circuit impedance value, the current oscillation frequency, and the rated frequency;

[0031] A first equivalent impedance value corresponding to the first impedance value and a second equivalent impedance value corresponding to the second impedance value are obtained through the reactance parallel branch of the double-tuned filter.

[0032] To solve the above technical problems, the present invention further provides a device for suppressing subsynchronous oscillation caused by grid connection of renewable energy, comprising:

[0033] an acquisition module, configured to activate a double-tuned filter and acquire a current oscillation frequency of the outgoing current of the wind farm when it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than a current threshold, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch;

[0034] An input module, configured to input the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch;

[0035] The adjustment module is used to adjust the first inductance value and the second inductance value to suppress subsynchronous oscillation when the first inductance value and the second inductance value meet preset conditions.

[0036] To solve the above technical problems, the present invention further provides a device for suppressing subsynchronous oscillation caused by grid connection of renewable energy, comprising:

[0037] Memory for storing computer programs;

[0038] The processor is configured to implement the steps of the above-mentioned method for suppressing subsynchronous oscillation caused by grid connection of new energy sources when executing a computer program.

[0039] To solve the above technical problems, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for suppressing subsynchronous oscillations caused by the grid connection of new energy are implemented.

[0040] The present invention provides a method for suppressing subsynchronous oscillations caused by the grid connection of renewable energy sources. The method includes: when a component current of a subsynchronous oscillation in a wind farm is detected to be greater than a current threshold, a double-tuned filter is activated and the current oscillation frequency is obtained. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; the current oscillation frequency is input into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; when the first inductance value and the second inductance value meet preset conditions, the first inductance value and the second inductance value are adjusted to suppress the subsynchronous oscillation. The method suppresses the subsynchronous components and supersynchronous components generated by the subsynchronous oscillation caused by the grid connection of renewable energy sources by determining the parameters of the double-tuned filter. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch, and then obtains the first inductance value and the second inductance value. When the first inductance value and the second inductance value meet the preset conditions, the first inductance value and the second inductance value are adjusted to suppress the subsynchronous oscillation. This method meets the subsynchronous oscillation suppression scenario caused by the grid connection of renewable energy sources and improves the operational reliability of the wind turbines in the wind farm.

[0041] In addition, the present invention also provides a device and medium for suppressing subsynchronous oscillation caused by renewable energy grid connection, which has the same beneficial effects as the above-mentioned method for suppressing subsynchronous oscillation caused by renewable energy grid connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1A flowchart of a method for suppressing subsynchronous oscillation caused by grid connection of renewable energy sources provided by an embodiment of the present invention;

[0044] Figure 2 A structural diagram of a subsynchronous filtering branch provided by an embodiment of the present invention;

[0045] Figure 3 A structural diagram of a super-synchronous filtering branch provided by an embodiment of the present invention;

[0046] Figure 4 A structural diagram of a device for suppressing subsynchronous oscillation caused by grid connection of renewable energy sources provided by an embodiment of the present invention;

[0047] Figure 5 A structural diagram of another device for suppressing subsynchronous oscillation caused by grid connection of new energy sources provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] The core of the present invention is to provide a method, device and medium for suppressing subsynchronous oscillation caused by renewable energy grid connection, meet the subsynchronous oscillation suppression scenario caused by renewable energy grid connection, and improve the operating reliability of wind turbines in wind farms.

[0050] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0051] It should be noted that the method provided by the present invention for suppressing subsynchronous oscillations caused by grid connection of renewable energy is applicable to subsynchronous oscillations occurring in wind farms without series compensation. The present invention is applicable to subsynchronous oscillations caused by grid connection of renewable energy without series compensation.

[0052] Figure 1 A flowchart of a method for suppressing subsynchronous oscillation caused by new energy grid connection is provided in an embodiment of the present invention. Figure 1 As shown, the method includes:

[0053] S11: When it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than the current threshold, the double-tuned filter is activated and the current oscillation frequency of the current wind farm outgoing line current is obtained, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch.

[0054] Existing measures to suppress subsynchronous oscillations caused by grid-connected renewable energy sources without series compensation conservatively remove a large number of wind turbines, but this will affect the efficiency of wind power generation and cause a certain amount of power loss. Therefore, when there is no subsynchronous oscillation, the double-tuned filter is disconnected by commanding the trip switch, isolating it from the wind farm, and there is no electrical connection between the two. This ensures that the double-tuned filter does not operate during normal operation of the wind farm, reducing energy loss during normal operation. When a subsynchronous oscillation component is detected in the wind farm's collection line and is greater than the trigger threshold, a closing command is issued. In other words, when it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than the current threshold, the double-tuned filter needs to be put into operation in a timely manner. When the component current is less than or equal to the current threshold, a trip command is issued to exit the double-tuned filter and continue normal operation.

[0055] Specifically, when the component current of the subsynchronous oscillation is greater than the current threshold, a double-tuned filter is activated. A double-tuned filter composed of a series-parallel combination of resistors, inductors, and capacitors, or composed of two single-tuned filters, can simultaneously absorb subsynchronous and supersynchronous components of two different frequencies, with minimal power loss at the fundamental frequency. The present invention employs a detuned filter equivalent method for parameter calculation of the double-tuned filter, where the subsynchronous or supersynchronous resonant circuit is equivalent to a single-tuned filter.

[0056] The present invention is aimed at the subsynchronous oscillation caused by the grid connection of renewable energy without series compensation. The double-tuned filter is respectively provided with a subsynchronous filter branch and a supersynchronous filter branch based on the subsynchronous frequency and the supersynchronous frequency.

[0057] It should be noted that the oscillation frequency of a wind farm when subsynchronous oscillation occurs is variable and belongs to a continuous variation range, and the frequency oscillation range is between 10-40Hz. For the existing double-tuned filter, it only targets discrete oscillation frequencies, such as the 50*v subfrequency point, where v is a positive integer from 1 to 50, and the existing double-tuned filter focuses on the reactive power provided by the fundamental frequency. The double-tuned harmonic filter designed in the present invention exits during normal operation of the wind farm and does not exchange reactive power with the wind farm, so the reactive power characteristics at the fundamental frequency are not considered. In addition, the existing double-tuned filter is mainly aimed at users or public power grid application scenarios containing harmonic pollution. The present invention is mainly aimed at subsynchronous oscillations caused by wind farms, specifically, subsynchronous oscillations caused by the grid connection of new energy in the subsynchronous oscillation action, which is generated due to the combined action of the special structure inside the wind turbine and the weak network structure, which is different from the application scenario of the existing double-tuned filter. Secondly, the characteristic harmonic frequencies of users and power grids containing harmonic sources in the application scenarios of the existing double-tuned filters are relatively fixed. The subsynchronous component targeted by the present invention not only has a rapidly changing frequency but is also relatively unstable, requiring a double-tuned filter for real-time tracking and judgment. In summary, the double-tuned filter designed by the present invention differs significantly from existing double-tuned filters in the nature of the oscillation frequency range, the characteristics of content variation, the nature of frequency variation, the position of the absolute frequency value, and the requirement for fundamental reactive power.

[0058] In this invention, when a component current is detected to be greater than a current threshold, the double-tuned filter is activated and the current oscillation frequency of the wind farm outgoing line current is obtained to suppress subsynchronous oscillations of the continuous oscillation frequency. When the component current is detected to be equal to or less than the current threshold, the double-tuned filter is deactivated, achieving energy conservation in the wind farm.

[0059] The parameter settings of the double-tuned filter are specifically set according to actual conditions. The parameter calculation methods for double-tuned filters with different structural forms are also different. The double-tuned filter of the present invention is based on the short-circuit capacity, frequency modulation parameters and parameter settings of different branches of the power grid system when the wind farm is connected to the power grid. It is only a preferred embodiment.

[0060] S12: Inputting the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch.

[0061] After the filter parameters that have been set in the above embodiment are determined, the current oscillation frequency is obtained. In the double-tuned filter, due to the current action of the subsynchronous oscillation frequency, the inductor and capacitor will undergo series resonance, satisfying the resonance relationship, and then the first inductance value and the second inductance value can be obtained by inputting the current oscillation frequency. Under the subsynchronous oscillation caused by the grid connection of new energy, the current oscillation frequency includes two types: subsynchronous oscillation frequency and supersynchronous oscillation frequency. The first inductance value obtained is the inductance value under the subsynchronous filter branch, and the second inductance value is the inductance value under the supersynchronous filter branch.

[0062] S13: When the first inductance value and the second inductance value meet a preset condition, adjustments are made to suppress subsynchronous oscillation.

[0063] The principle of the double-tuned filter is to convert the detected subsynchronous oscillation frequency into a first inductance value and a second inductance value. According to the inherent mapping relationship between the DC control voltage and the inductance, the first inductance value and the second inductance value are converted into a DC control voltage. The DC control voltage is changed to change the output reactance value of the controllable reactor. That is, the first inductance value and the second inductance value can be adjusted after meeting the preset conditions to achieve regulation to suppress subsynchronous oscillation.

[0064] Specifically, the preset condition can be that the first inductance value and the second inductance value are within the corresponding preset inductance range, or other conditions can be met. As long as the preset condition is met, the reactance value can be adjusted. The preset inductance range can be obtained by any of three methods: the operating mode of the power grid, the subsynchronous oscillation frequency, and the capacitance values ​​corresponding to different branches of the double-tuned filter. It can be any one of the three methods, or a combination of any two, or a combination of three. The present invention is not limited to this, and the three combinations are only one preferred embodiment.

[0065] The present invention provides a method for suppressing subsynchronous oscillations caused by the grid connection of renewable energy sources. The method includes: when a component current of a subsynchronous oscillation in a wind farm is detected to be greater than a current threshold, a double-tuned filter is activated and the current oscillation frequency is obtained. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; the current oscillation frequency is input into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; when the first inductance value and the second inductance value meet preset conditions, the first inductance value and the second inductance value are adjusted to suppress the subsynchronous oscillation. The method suppresses the subsynchronous components and supersynchronous components generated by the subsynchronous oscillation caused by the grid connection of renewable energy sources by determining the parameters of the double-tuned filter. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch, and then obtains the first inductance value and the second inductance value. When the first inductance value and the second inductance value meet the preset conditions, the first inductance value and the second inductance value are adjusted to suppress the subsynchronous oscillation. This method meets the subsynchronous oscillation suppression scenario caused by the grid connection of renewable energy sources and improves the operational reliability of the wind turbines in the wind farm.

[0066] Based on the above embodiment, the parameters of the double-tuned filter can be determined in the following way:

[0067] Obtain the voltage data and reactive power of the wind farm to obtain the short-circuit capacity of the grid when the wind farm is connected to the grid;

[0068] Determine a first equivalent impedance value of the subsynchronous filter branch and a second equivalent impedance value of the supersynchronous filter branch according to the relationship between the short-circuit capacity, the rated voltage value, the current oscillation frequency and the rated frequency;

[0069] Determining a first reactance parameter and a first capacitance parameter corresponding to the sub-synchronous filter branch according to the first equivalent impedance value and the factor number of the sub-synchronous filter branch;

[0070] The second reactance parameter and the second capacitance parameter corresponding to the super synchronous filter branch are determined according to the second equivalent impedance and the factor number of the super synchronous filter branch to obtain the parameters of the double tuned filter.

[0071] Specifically, the wind farm's Supervisory Control And Data Acquisition (SCADA) system collects one year's worth of wind power main transformer low-voltage side voltage data Ui (i = integer 1-365) and reactive power Qi (if there is no main transformer, the grid connection point voltage Ui and reactive power Qi are collected). The equivalent system short-circuit capacity Si is then obtained daily. The relationship among Si, Ui, and Qi is as follows:

[0072]

[0073] Where Qi(95%) is the maximum value of Qi with 95% probability on day i. Qi(5%) is the maximum value of Qi with 5% probability on day i. Ui(95%) is the maximum value of Ui with 95% probability on day i. Ui(5%) is the maximum value of Ui with 5% probability on day i.

[0074] According to the short-circuit capacity Si, rated voltage value U n , current oscillation frequency f and rated frequency f n The relationship between the first equivalent impedance value Z of the subsynchronous filter branch is determined sub and the second equivalent impedance value Z of the super synchronous filter branch sup , where the rated voltage value is U n The rated voltage of the low-voltage side of the main transformer. If there is no main transformer for wind power, U n is the grid connection point voltage rating.

[0075] The double-tuned filter consists of a subsynchronous filter branch and a supersynchronous filter branch. The parameters of the two filter branches are as follows:

[0076] The equivalent subsynchronous filter branch consists of inductor L1, capacitor C1, and resistor R1. Figure 2 A structural diagram of a subsynchronous filtering branch provided by an embodiment of the present invention, such as Figure 2 As shown, under the action of the current of the subsynchronous oscillation frequency fs, the inductor L1 and the capacitor C1 will have a series resonance effect, and at this time:

[0077]

[0078] When the current at the subsynchronous frequency fs flows through the subsynchronous filter branch, the impedance of the inductor L1 and the capacitor C1 is equal to 0, and the fundamental impedance of the subsynchronous filter branch is equal to the value of Ra, which is expressed as follows:

[0079]

[0080] Since the equivalent impedance value is the same as the fundamental impedance value under the condition of complete resonance, Ra obtains the first equivalent impedance value and Rb obtains the second equivalent impedance value.

[0081] Determining a first reactance parameter La and a first capacitance parameter Ca corresponding to the sub-synchronous filter branch according to the first equivalent impedance value Ra and the factor number Qa of the sub-synchronous filter branch specifically includes:

[0082] Define the factor Qa of the subsynchronous filter branch as 50 = Xa / Ra, where Xa is the reactance value of the subsynchronous filter branch at the fundamental frequency. The subsynchronous filter branch Za (approximately equal to Xa) under fundamental conditions can be calculated to be equal to:

[0083] Z a=50*R a

[0084] The Za of the subsynchronous filter branch under fundamental conditions is mainly composed of inductor L1 and capacitor C1 (ignoring the effect of Ra because), and the corresponding expression can be written:

[0085]

[0086] By combining the formulas for series resonance, Ra, the subsynchronous filter branch Za, and the subsynchronous filter branch Za under fundamental conditions, we can derive the expressions for the first reactance parameter La and the first capacitance parameter Ca:

[0087]

[0088] Then we can conclude that:

[0089]

[0090]

[0091] The equivalent super synchronous filter branch consists of inductor L2, capacitor C2, and resistor R2. Figure 3 A structural diagram of a super-synchronous filtering branch provided by an embodiment of the present invention is shown in FIG. Figure 3 As shown, under the action of the current of the supersynchronous oscillation frequency fp, the inductor L2 and the capacitor C2 will have a series resonance effect, and at this time:

[0092]

[0093] When the current at the super-synchronous frequency fp flows through the super-synchronous filter branch, the super-synchronous harmonic current amplitude of the super-synchronous filter branch is 10 times that of the system branch. Based on the reactance parallel branch, the equivalent impedance value Zsup of the equivalent super-synchronous filter branch at full resonance can be calculated as:

[0094]

[0095] Define the super-synchronous filter branch factor Qb = 50 = Xb / Rb, Xb is the fundamental reactance value of the super-synchronous branch. It can be calculated that the super-synchronous filter branch Zb under fundamental conditions is approximately equal to:

[0096] Z b =-50*R b

[0097] The super synchronous filter branch Zb under fundamental wave conditions is mainly composed of inductor L2 and capacitor C2 (ignoring the effect of Rb because), and the corresponding expression can be written:

[0098]

[0099] By combining the formulas for series resonance, Rb, the super-synchronous filter branch Zb, and the super-synchronous filter branch Zb under fundamental conditions, we can derive the expressions for the second reactance parameter Lb and the second capacitance parameter Cb:

[0100]

[0101] Then we can conclude that:

[0102]

[0103]

[0104] The determined parameters of the double-tuned filter provided in this embodiment suppress the subsynchronous frequency and supersynchronous frequency generated by the subsynchronous oscillation caused by the grid connection of new energy sources through the determined double-tuned filter. The double-tuned filter includes the design of a subsynchronous filter branch and a supersynchronous filter branch, which meets the subsynchronous oscillation suppression scenario caused by the grid connection of new energy sources and improves the operating reliability of wind turbines in wind farms.

[0105] In the above embodiment, the preset conditions are that the first inductance value is within a first preset inductance value range and the second inductance value is within a second preset inductance value range;

[0106] The minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by at least one of three methods: the operation mode of the power grid, the subsynchronous oscillation frequency, and the capacitance values ​​corresponding to different branches of the double-tuned filter.

[0107] L1 in the subsynchronous branch and L2 in the supersynchronous branch are adjustable reactances, and their adjustable range needs to meet preset conditions. The preset range of the preset conditions can be obtained by any one of three methods: the operation time of the wind farm, the subsynchronous oscillation frequency, and the capacitance values ​​corresponding to different branches of the double-tuned filter.

[0108] For the operation mode of the power grid, it is the operation requirements under the minimum short-circuit capacity and maximum short-circuit capacity of the power grid; for the subsynchronous oscillation frequency, it is the requirement for the subsynchronous oscillation frequency to change from the minimum to the maximum range; for the influence of capacitance deviation, the range from the rated capacitance value to the maximum capacitance value meets the requirements.

[0109] It should be noted that the preset range is based on the expression of the first reactance parameter and the second reactance parameter. Only any one of the above three methods, or a combination of any two methods, or all three methods can be satisfied. The present invention does not make specific limitations and can be set according to the specific wind farm situation. It is only an optimal embodiment.

[0110] The preset conditions provided in this embodiment can be used to adjust the resonant frequency by adjusting the reactance as long as the preset conditions are met, thereby further suppressing subsynchronous oscillations.

[0111] In a specific embodiment, the preset range in the preset condition is obtained by the operation mode of the power grid, which is as follows:

[0112] Obtain the maximum short-circuit capacity and the minimum short-circuit capacity among the short-circuit capacities;

[0113] Determine the minimum fundamental short-circuit impedance based on the maximum short-circuit capacity and rated voltage value;

[0114] Determine the maximum fundamental short-circuit impedance based on the minimum short-circuit capacity and rated voltage;

[0115] The minimum first inductance value and the minimum second inductance value under the minimum operation mode of the power grid and the maximum first inductance value and the maximum second inductance value under the maximum operation mode of the power grid are determined according to the maximum fundamental short-circuit impedance and the minimum fundamental short-circuit impedance, and the first reactance parameter and the second reactance parameter.

[0116] Specifically, the maximum short-circuit capacity S is obtained from the short-circuit capacity max , the formula is as follows:

[0117] S max =max(S1…S i …S 365 )

[0118] Get the minimum short-circuit capacity S in the short-circuit capacity min , obtained by the following formula:

[0119] S min =min(S1…S i …S 365 )

[0120] According to the minimum short-circuit capacity S min Determine the maximum fundamental short-circuit impedance X with the rated voltage Un max , the formula is as follows:

[0121]

[0122] Similarly, according to the maximum short-circuit capacity S max Determine the minimum fundamental short-circuit impedance X with the rated voltage Unmin , the formula is as follows:

[0123]

[0124] Generally, the relationship between the short-circuit capacity Si, the rated voltage Un, and the fundamental short-circuit impedance Xi is expressed by the following formula:

[0125]

[0126] It can be seen from the expression of the first reactance parameter La under the subsynchronous filter branch that La is proportional to the fundamental impedance of the system. When the fundamental impedance is larger, the corresponding La value is larger. When the fundamental impedance is smaller, the corresponding La is smaller. From the above rules, it can be seen that the fundamental impedance value X under the maximum operation mode of the power grid is min Corresponding to the minimum first inductance value, the fundamental impedance value X under the minimum operation mode of the power grid max Corresponding to the maximum first inductance value.

[0127] Similarly, the fundamental impedance value X under the maximum operation mode of the power grid min Corresponding to the minimum second inductance value, the fundamental impedance value X under the minimum operation mode of the power grid max Corresponding to the second largest inductance value.

[0128] The preset range provided in this embodiment is obtained by obtaining the minimum first inductance value, the minimum second inductance value, the maximum first inductance value and the maximum second inductance value under the operation mode of the power grid. When the preset range under the maximum and minimum operation modes of the power grid is met, the reactance value is adjusted.

[0129] Based on the above embodiment, the preset range in the preset condition is obtained by means of a subsynchronous oscillation frequency, specifically as follows:

[0130] Obtain the minimum oscillation frequency and the maximum oscillation frequency among the oscillation frequencies;

[0131] The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the minimum oscillation frequency, the maximum oscillation frequency, the first reactance parameter, and the second reactance parameter.

[0132] Specifically, in combination with the above embodiment, the first reactance parameter La and the subsynchronous oscillation frequency fs in the oscillation frequency can be obtained as follows:

[0133]

[0134] From the above formula, we can see that the expression of La is mainly divided into two parts. The first part is is a monotonically increasing function. The second part is It is also a monotonically increasing function. Summarizing the function characteristics of the two parts, La is a monotonically increasing function of fs.

[0135] Similarly, the second reactance parameter Lb and the subsynchronous oscillation frequency fs in the oscillation frequency can be obtained by the following formula:

[0136]

[0137] Combined with the first part is a monotonically increasing function. Part 2 It is a non-monotonic function. Summarizing the function characteristics of the two parts, Lb is a non-monotonic function of fs, and a search function is needed to find the maximum and minimum values ​​of Lb.

[0138] Therefore, the minimum first inductance value, the minimum second inductance value, the maximum first inductance value and the maximum second inductance value can be obtained according to the minimum oscillation frequency and the maximum oscillation frequency.

[0139] The preset range provided in this embodiment is achieved by obtaining a minimum first inductance value, a minimum second inductance value, a maximum first inductance value, and a maximum second inductance value in a subsynchronous oscillation frequency manner. When the preset range under the requirement that the subsynchronous oscillation frequency varies from the minimum to the maximum range is met, the reactance value is adjusted.

[0140] Based on the above embodiment, the preset range in the preset condition is obtained by means of the capacitance value corresponding to the short-circuit capacity, as follows:

[0141] Get the rated capacitance value and the maximum capacitance value of the capacitor;

[0142] The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the rated capacitance value, the maximum capacitance value, the first reactance parameter, and the second reactance parameter.

[0143] Specifically, the rated capacitance value is the designed capacitance value, and the maximum capacitance value is 1.05 times the rated capacitance value, and the preset range is determined according to the expression of the first reactance parameter and the second reactance parameter.

[0144] When the three methods are combined as the preset condition, the maximum first inductance value L amax It can be obtained by the following expression:

[0145]

[0146] Among them: max is the maximum value function.

[0147] Minimum first inductance value L amin It can be obtained by the following expression:

[0148]

[0149] Among them: min is the minimum value function.

[0150] Maximum second inductance value Lbmax It can be obtained by the following expression:

[0151]

[0152] Among them: max is the maximum value function.

[0153] Minimum second inductance value Lbmin It can be obtained by the following expression:

[0154]

[0155] Among them: min is the minimum value function.

[0156] In order to facilitate the feasibility verification of the inductance parameters, check whether the maximum and minimum values ​​of the first inductance and the second inductance are between 1% and 100% of the rated inductance. If they are within the rated inductance range, it means that the resonant frequency can be adjusted by adjusting the inductance. Otherwise, it means that the inductance cannot be adjusted to achieve the adjustment of the resonant frequency, and the parameters of the double-tuned filter are unqualified.

[0157] During parameter verification, all variables are set to per-unit values. The value range of fs is 0.2fn to 0.8fn. Smin is 0.6, Smax is 5, Un is 1, and fn is 1.

[0158] Substituting each parameter into the expression of the minimum first inductance value and the maximum first inductance value, L can be calculated. amax =2.94, L amin =0.0331, we can find the ratio of the two, and the corresponding ratio is:

[0159]

[0160] As can be seen from the above formula, the adjustable range of the sub-synchronous branch is about 89 times, which is smaller than the design ratio of 100 times and satisfies the adjustable range of the inductor L1.

[0161] Substituting each parameter into the expression of the minimum second inductance value and the maximum second inductance value, L can be calculated. bmax =6.8, L bmin =0.648, we can find the ratio of the two, and the corresponding ratio is:

[0162]

[0163] It can be seen from the above formula that the adjustable range of the super synchronous branch is about 10.5 times, which is smaller than the design ratio of 100 times and satisfies the adjustable range of the inductor L2.

[0164] The preset range provided in this embodiment is to obtain the minimum first inductance value, the minimum second inductance value, the maximum first inductance value and the maximum second inductance value under the rated voltage value, and to achieve the adjustment of the reactance value when the requirements of the range from the rated capacitance value to the maximum capacitance value are met.

[0165] In a specific embodiment, the current oscillation frequency obtained includes a subsynchronous oscillation frequency and a supersynchronous oscillation frequency, and the first equivalent impedance value of the subsynchronous filter branch and the second equivalent impedance value of the supersynchronous filter branch are determined according to the relationship between the short-circuit capacity, the rated voltage value, the current oscillation frequency, and the rated frequency, including:

[0166] Determine the fundamental short-circuit impedance value based on the relationship between the short-circuit capacity and the rated voltage value;

[0167] Determine a first impedance value at a subsynchronous oscillation frequency and a second impedance value at a supersynchronous oscillation frequency according to the fundamental wave short-circuit impedance value, the current oscillation frequency, and the rated frequency;

[0168] A first equivalent impedance value corresponding to the first impedance value and a second equivalent impedance value corresponding to the second impedance value are obtained through the reactance parallel branch of the double-tuned filter.

[0169] Generally, the relationship between the short-circuit capacity Si, the rated voltage Un, and the fundamental short-circuit impedance Xi is expressed by the following formula:

[0170]

[0171] Specifically, the system impedance changes linearly with the frequency in the subsynchronous oscillation frequency band. The first impedance value Xsub at the subsynchronous frequency under the maximum operation mode of the power grid can be calculated using the following formula:

[0172]

[0173] Where fs is the subsynchronous oscillation frequency and fn is the rated frequency.

[0174] Similarly, the second impedance value X at the super-synchronous oscillation frequency under the maximum operation mode of the power grid is sup for:

[0175]

[0176] Typically, the first impedance value Xsub at the subsynchronous frequency is:

[0177]

[0178] The second impedance value Xsup at the supersynchronous oscillation frequency is:

[0179]

[0180] The subsynchronous harmonic current amplitude of the filter branch is 10 times that of the system branch. Based on the reactance parallel branch, the first equivalent impedance value Zsub of the equivalent subsynchronous filter branch at full resonance can be calculated as follows:

[0181]

[0182] Its second equivalent impedance value Zsup is as follows:

[0183]

[0184] This embodiment provides a method for determining the first equivalent impedance value and the second equivalent impedance value, and obtains the equivalent impedance value under full resonance in combination with the subsynchronous oscillation caused by the specific new energy grid connection, which facilitates the final determination of the subsequent filter parameters.

[0185] The above describes in detail various embodiments corresponding to the method for suppressing subsynchronous oscillations caused by the grid connection of renewable energy. On this basis, the present invention also discloses a device for suppressing subsynchronous oscillations caused by the grid connection of renewable energy corresponding to the above method. Figure 4 This is a structural diagram of a device for suppressing subsynchronous oscillation caused by new energy grid connection provided by an embodiment of the present invention. Figure 4 As shown, the device for suppressing subsynchronous oscillation caused by the grid connection of new energy sources includes:

[0186] an acquisition module 11, configured to activate a double-tuned filter and acquire a current oscillation frequency of the outgoing current of the wind farm when it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than a current threshold, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch;

[0187] An input module 12 is configured to input the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch;

[0188] The adjustment module 13 is configured to perform adjustment when the first inductance value and the second inductance value meet a preset condition to suppress subsynchronous oscillation.

[0189] Since the embodiments of the device part correspond to the above embodiments, the embodiments of the device part please refer to the description of the embodiments of the method part, which will not be repeated here.

[0190] The present invention provides a device for suppressing subsynchronous oscillations caused by renewable energy grid connection. The device comprises: when a component current of a subsynchronous oscillation in a wind farm is detected to be greater than a current threshold, a double-tuned filter is activated and the current oscillation frequency is obtained. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; the current oscillation frequency is input into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; when the first inductance value and the second inductance value meet preset conditions, the device adjusts the first inductance value and the second inductance value to suppress subsynchronous oscillations. The device suppresses subsynchronous components and supersynchronous components generated by subsynchronous oscillations caused by renewable energy grid connection by determining the parameters of the double-tuned filter. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch, and then obtains the first inductance value and the second inductance value. When the first inductance value and the second inductance value meet preset conditions, the device adjusts the first inductance value and the second inductance value to suppress subsynchronous oscillations. This device meets the subsynchronous oscillation suppression scenario caused by renewable energy grid connection and improves the operational reliability of wind turbines in wind farms.

[0191] Figure 5 A structural diagram of another device for suppressing subsynchronous oscillation caused by new energy grid connection provided by an embodiment of the present invention, such as Figure 5 As shown, the device includes:

[0192] Memory 21, for storing computer programs;

[0193] The processor 22 is configured to implement the steps of the method for suppressing subsynchronous oscillation caused by grid connection of new energy sources when executing a computer program.

[0194] The device for suppressing subsynchronous oscillation caused by grid connection of renewable energy provided in this embodiment may include but is not limited to a smart phone, a tablet computer, a laptop computer, or a desktop computer.

[0195] Among them, the processor 22 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 22 can be implemented in at least one hardware form of a digital signal processor (DSP), a field programmable gate array (FPGA), and a programmable logic array (PLA). The processor 22 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 22 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 22 may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0196] The memory 21 may include one or more computer-readable storage media, which may be non-transitory. The memory 21 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In this embodiment, the memory 21 is used to store at least the following computer program 211, wherein, after the computer program is loaded and executed by the processor 22, it can implement the relevant steps of the method for suppressing subsynchronous oscillations caused by the grid connection of new energy sources disclosed in any of the aforementioned embodiments. In addition, the resources stored in the memory 21 may also include an operating system 212 and data 213, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system 212 may include Windows, Unix, Linux, etc. The data 213 may include but is not limited to data related to the method for suppressing subsynchronous oscillations caused by the grid connection of new energy sources, etc.

[0197] In some embodiments, the device for suppressing subsynchronous oscillation caused by grid connection of new energy may further include a display screen 23 , an input / output interface 24 , a communication interface 25 , a power supply 26 , and a communication bus 27 .

[0198] Those skilled in the art will understand that Figure 5 The structure shown in the figure does not constitute a limitation on the device for suppressing subsynchronous oscillation caused by the grid connection of renewable energy, and may include more or fewer components than shown in the figure.

[0199] The processor 22 calls the instructions stored in the memory 21 to implement the method for suppressing subsynchronous oscillation caused by the grid connection of new energy provided by any of the above embodiments.

[0200] The present invention provides a device for suppressing subsynchronous oscillations caused by renewable energy grid connection. The device comprises: when a component current of a subsynchronous oscillation in a wind farm is detected to be greater than a current threshold, a double-tuned filter is activated and the current oscillation frequency is obtained. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; the current oscillation frequency is input into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; when the first inductance value and the second inductance value meet preset conditions, the device adjusts the first inductance value and the second inductance value to suppress subsynchronous oscillations. The device suppresses subsynchronous components and supersynchronous components generated by subsynchronous oscillations caused by renewable energy grid connection by determining the parameters of the double-tuned filter. The double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch, and then obtains the first inductance value and the second inductance value. When the first inductance value and the second inductance value meet preset conditions, the device adjusts the first inductance value and the second inductance value to suppress subsynchronous oscillations. This device meets the subsynchronous oscillation suppression scenario caused by renewable energy grid connection and improves the operational reliability of wind turbines in wind farms.

[0201] Furthermore, the present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by the processor 22, the steps of the method for suppressing subsynchronous oscillation caused by the grid connection of new energy sources as described above are implemented.

[0202] It is understandable that if the method in the above embodiment is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and executes all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0203] For an introduction to a computer-readable storage medium provided by the present invention, please refer to the above method embodiment, which will not be described in detail herein. It has the same beneficial effects as the above method for suppressing subsynchronous oscillations caused by new energy grid connection.

[0204] The above is a detailed introduction to the method, device and medium for suppressing subsynchronous oscillations caused by the grid connection of new energy sources provided by the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0205] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A method for suppressing subsynchronous oscillation caused by renewable energy grid connection, characterized in that: include: When it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than the current threshold, the double-tuned filter is activated and the current oscillation frequency of the current outgoing current of the wind farm is obtained, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; Inputting the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; When the first inductance value and the second inductance value meet a preset condition, adjustment is performed to complete the suppression of the subsynchronous oscillation; wherein the preset condition is that the first inductance value is within a preset range of first inductance values ​​and the second inductance value is within a preset range of second inductance values; correspondingly, the minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by at least one of three methods: an operating mode of the power grid, a subsynchronous oscillation frequency, and capacitance values ​​corresponding to different branches of the double-tuned filter.

2. The method for suppressing subsynchronous oscillation caused by renewable energy grid connection according to claim 1, characterized in that: The parameters of the double-tuned filter are obtained as follows: Acquiring voltage data and reactive power of the wind farm to obtain the short-circuit capacity of the power grid when the wind farm is connected to the power grid; Determining a first equivalent impedance value of the subsynchronous filter branch and a second equivalent impedance value of the supersynchronous filter branch according to the short-circuit capacity, the rated voltage value, and a relationship between the current oscillation frequency and the rated frequency; Determining a first reactance parameter and a first capacitance parameter corresponding to the sub-synchronous filter branch according to the first equivalent impedance value and the factor number of the sub-synchronous filter branch; The second reactance parameter and the second capacitance parameter corresponding to the super synchronous filter branch are determined according to the second equivalent impedance and the factor number of the super synchronous filter branch to obtain the parameters of the double tuned filter.

3. The method for suppressing subsynchronous oscillation caused by new energy grid connection according to claim 2, characterized in that: The minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by the operating mode of the power grid, specifically as follows: Obtaining a maximum short-circuit capacity and a minimum short-circuit capacity among the short-circuit capacities; Determining a minimum fundamental short-circuit impedance according to the maximum short-circuit capacity and the rated voltage value; Determining a maximum fundamental short-circuit impedance according to the minimum short-circuit capacity and the rated voltage value; The minimum first inductance value and the minimum second inductance value under the minimum operating mode of the power grid and the maximum first inductance value and the maximum second inductance value under the maximum operating mode of the power grid are determined according to the maximum fundamental short-circuit impedance and the minimum fundamental short-circuit impedance, and the first reactance parameter and the second reactance parameter.

4. The method for suppressing subsynchronous oscillation caused by renewable energy grid connection according to claim 2, characterized in that: The minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by the subsynchronous oscillation frequency method, which is specifically as follows: Obtain the minimum oscillation frequency and the maximum oscillation frequency among the oscillation frequencies; The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the minimum oscillation frequency, the maximum oscillation frequency, and the first reactance parameter and the second reactance parameter.

5. The method for suppressing subsynchronous oscillation caused by renewable energy grid connection according to claim 2, characterized in that: The minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by means of capacitance values ​​corresponding to different branches of the double-tuned filter, which are specifically as follows: Obtaining a rated capacitance value and a maximum capacitance value of the capacitance value; The minimum first inductance value, the minimum second inductance value, the maximum first inductance value, and the maximum second inductance value are determined according to the rated capacitance value, the maximum capacitance value, and the first reactance parameter and the second reactance parameter.

6. The method for suppressing subsynchronous oscillation caused by renewable energy grid connection according to claim 2, characterized in that: The current oscillation frequency includes a subsynchronous oscillation frequency and a supersynchronous oscillation frequency, and determining the first equivalent impedance value of the subsynchronous filter branch and the second equivalent impedance value of the supersynchronous filter branch according to the relationship between the short-circuit capacity, the rated voltage value, the current oscillation frequency, and the rated frequency includes: Determining a fundamental short-circuit impedance value according to a relationship between the short-circuit capacity and the rated voltage value; determining a first impedance value at the subsynchronous oscillation frequency and a second impedance value at the supersynchronous oscillation frequency according to the fundamental short-circuit impedance value, the current oscillation frequency, and the rated frequency; The first equivalent impedance value corresponding to the first impedance value and the second equivalent impedance value corresponding to the second impedance value are obtained through the reactance parallel branch of the double-tuned filter.

7. A device for suppressing subsynchronous oscillation caused by grid connection of renewable energy, characterized in that: include: an acquisition module, configured to activate a double-tuned filter and acquire a current oscillation frequency of the outgoing current of the wind farm when it is detected that the component current of the subsynchronous oscillation of the wind farm is greater than a current threshold, wherein the double-tuned filter includes a subsynchronous filter branch and a supersynchronous filter branch; an input module, configured to input the current oscillation frequency into the double-tuned filter to obtain a first inductance value and a second inductance value, wherein the first inductance value is the inductance value of the subsynchronous filter branch, and the second inductance value is the inductance value of the supersynchronous filter branch; an adjustment module, configured to adjust the first inductance value and the second inductance value to suppress the subsynchronous oscillation when the first inductance value and the second inductance value meet a preset condition; wherein the preset condition is that the first inductance value is within a preset range of first inductance values ​​and the second inductance value is within a preset range of second inductance values; correspondingly, the minimum first inductance value and the maximum first inductance value within the preset range of the first inductance value, and the minimum second inductance value and the maximum second inductance value within the preset range of the second inductance value are obtained by at least one of three methods: an operating mode of the power grid, a subsynchronous oscillation frequency, and capacitance values ​​corresponding to different branches of the double-tuned filter.

8. A device for suppressing subsynchronous oscillation caused by grid connection of renewable energy, characterized in that: include: memory for storing computer programs; A processor, configured to implement the steps of the method for suppressing subsynchronous oscillation caused by grid connection of new energy sources as claimed in any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for suppressing subsynchronous oscillation caused by grid connection of new energy sources according to any one of claims 1 to 6.

Images