Wideband oscillation risk assessment method, system and equipment for wind power plant access power grid and medium

Abstract

The invention discloses a broadband oscillation risk assessment method, system and device for a wind power plant access power grid, and a medium. The method comprises the following steps: establishing an electromagnetic transient model of a wind power converter and an electromagnetic transient model of a static var generator (SVG); calculating equivalent machine parameters, shafting parameters, equivalent box transformer substation parameters and current collection line parameters of the wind power station; constructing an equivalent model of the wind power station according to the electromagnetic transient model of the wind power converter, the electromagnetic transient model of the static var generator SVG and equivalent machine parameters, shafting parameters, equivalent box transformer parameters and current collection line parameters of the wind power station; simulating positive sequence and negative sequence oscillation signals according to the equivalent model of the wind power station; and according to the simulated positive-sequence and negative-sequence oscillation signals, carrying out risk assessment on broadband oscillation of the wind power plant access power grid. The method, the system, the equipment and the medium can accurately assess the risk of broadband oscillation of the wind power plant access power grid.

Description

Technical Field

[0001] The invention belongs to the field of wind power generation, and relates to a method, system, equipment and medium for assessing the broadband oscillation risk of a wind farm station connected to a power grid. Background Art

[0002] Large-scale grid connection of new energy generation technologies such as wind power and photovoltaic power generation has become an important part of the power system that cannot be ignored. However, this also increases the risk of broadband oscillation in the power system. Broadband oscillation is an electronic technology phenomenon, which is characterized by the fact that the frequency of the signal waveform is not fixed, but fluctuates irregularly or periodically within a relatively wide range. The broadband oscillation in the photovoltaic power generation grid-connected system is manifested in the unstable fluctuation of the frequency of key electrical quantities such as system voltage and current within a wide frequency band. This fluctuation not only has a wide frequency range, but may also be accompanied by significant changes in amplitude, thus posing a serious threat to the stability of the power system.

[0003] In recent years, the causes, analytical methods and suppression strategies of broadband oscillations in the process of wind power grid connection have become a hot topic of common concern in domestic and foreign academic and industrial circles, and many breakthrough results have been achieved in this field. However, in the field of risk assessment of broadband oscillations in wind power grid-connected systems, related research is still in its infancy and needs further in-depth exploration and detailed analysis. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method, system, device and medium for assessing the risk of broadband oscillation when a wind farm is connected to a power grid. The method, system, device and medium can accurately assess the risk of broadband oscillation when a wind farm is connected to a power grid.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] In one aspect, the present invention provides a method for assessing the broadband oscillation risk of a wind farm station connected to a power grid, comprising the following steps:

[0007] Collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm;

[0008] According to the actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm station, an electromagnetic transient model of the wind power converter and an electromagnetic transient model of the static VAR generator SVG are established;

[0009] Calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station;

[0010] According to the electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG and the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm, an equivalent model of the wind farm is constructed;

[0011] Simulating positive-sequence and negative-sequence oscillation signals according to an equivalent model of the wind farm station;

[0012] The risk assessment of broadband oscillation of wind farm access to the power grid is performed based on the simulated positive-sequence and negative-sequence oscillation signals.

[0013] The method for assessing the risk of broadband oscillation when a wind farm is connected to a power grid according to the present invention is further improved in that:

[0014] Furthermore, before constructing the equivalent model of the wind farm according to the electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG and the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm, the equivalent model of the wind farm may also include:

[0015] The electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG are simulated and verified.

[0016] Furthermore, the equivalent machine parameters are:

[0017]

[0018] Among them, S eq is the capacity of the equivalent unit, P eq is the equivalent unit active power, Q eq is the equivalent unit reactive power, X m is the magnetizing reactance, R s is the stator resistance, R r is the rotor resistance, X s is the stator reactance, X r is the rotor reactance. i represents the parameters of the i-th unit.

[0019] Furthermore, the axis system parameters are:

[0020]

[0021] Among them, H eq is the inertia time constant, K eq is the shaft stiffness coefficient, D eq is the shaft damping coefficient, and i represents the damping coefficient of the i-th wind turbine unit.

[0022] Furthermore, the equivalent box transformer parameters are:

[0023]

[0024] Among them, S t is the capacity of a single box transformer, Z t It is the impedance of a single box transformer.

[0025] Furthermore, the calculation process of the collector line parameters is:

[0026] The equivalent impedance of the collector line is determined by the principle of consistent grid connection point loss. The equivalent impedance of the dry-connected collector line is:

[0027]

[0028] The equivalent impedance of the radially connected collector is:

[0029]

[0030] According to the size of the collector line impedance and the power distribution size, the equivalent impedance of the wind power station collector line is:

[0031]

[0032] Among them, Z eq is the equivalent impedance of the collector line, Zi is the impedance of the busbar collector line from the ith unit to the feeder grid connection point, N is the number of equivalent units, X is the average number of units per feeder in the wind power station, and Y is the number of collection lines.

[0033] Furthermore, the process of performing risk assessment of broadband oscillation of wind farm access to the power grid according to the simulated positive-sequence and negative-sequence oscillation signals is as follows:

[0034] Introducing harmonic injection module into the equivalent model of wind farm station to simulate positive and negative sequence oscillation signals;

[0035] Based on the simulated positive-sequence and negative-sequence oscillation signals, the risk of broadband oscillation of wind farms connected to the power grid is assessed using Bode plots and Nyquist plots.

[0036] In a second aspect of the present invention, the present invention provides a system for assessing the risk of broadband oscillation when a wind farm is connected to a power grid, comprising:

[0037] The acquisition module is used to collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm station;

[0038] Establishing a module for establishing an electromagnetic transient model of the wind power converter and an electromagnetic transient model of the static VAR generator SVG according to actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm station;

[0039] The calculation module is used to calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station;

[0040] A construction module is used to construct an equivalent model of a wind farm station according to an electromagnetic transient model of a wind power converter and an electromagnetic transient model of a static VAR generator SVG and equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station;

[0041] A simulation module, used for simulating positive sequence and negative sequence oscillation signals according to an equivalent model of the wind farm station;

[0042] The evaluation module is used to evaluate the risk of broadband oscillation of a wind farm station connected to a power grid according to the simulated positive-sequence and negative-sequence oscillation signals.

[0043] In a third aspect of the present invention, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for assessing the risk of broadband oscillation of a wind farm connected to a power grid are implemented.

[0044] In a fourth aspect of the present invention, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for assessing the risk of broadband oscillation of a wind farm connected to a power grid are implemented.

[0045] The present invention has the following beneficial effects:

[0046] The method, system, device and medium for assessing the risk of broadband oscillation when a wind farm is connected to a power grid described in the present invention take into account the relationship between the oscillation frequency coupling phenomenon and the characteristics of the wind farm itself during specific operation, accurately judge the actual stable state of a high-proportion wind power system, and eliminate the risk of misjudgment of system stability. Positive-sequence and negative-sequence oscillation signals are simulated according to the equivalent model of the wind farm, and the risk of broadband oscillation when the wind farm is connected to a power grid is assessed based on the simulated positive-sequence and negative-sequence oscillation signals. The operation is simple, convenient and extremely practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0048] Figure 1 is a flow chart of the method of the present invention;

[0049] Figure 2 This is the topological diagram of the electromagnetic transient model of the NEPCS-1250 wind power converter;

[0050] Figure 3 This is the topological diagram of the electromagnetic transient model of FGSVG-C30.0 / 35-0-W SVG;

[0051] Figure 4 This is the result diagram of electromagnetic transient model verification for NEPCS-1250 wind power converter;

[0052] Figure 5 This is the result diagram of electromagnetic transient model verification of FGSVG-C30.0 / 35-0-W SVG;

[0053] Figure 6 This is the equivalent model diagram of the wind farm station;

[0054] Figure 7 This is the calibration result diagram of the equivalent model of the wind farm station;

[0055] Figure 8 Topology diagram for harmonic injection module;

[0056] Fig. 9 Bode diagram and Nyquist diagram for positive sequence signal;

[0057] Fig.10 Bode plot and Nyquist plot for negative sequence signal. DETAILED DESCRIPTION

[0058] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0059] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

[0060] refer to Figure 1 The method for assessing the risk of broadband oscillation when a wind farm is connected to a power grid according to the present invention comprises the following steps:

[0061] 1) Collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm.

[0062] Specifically, an electromagnetic transient model of a wind power converter and an electromagnetic transient model of a static VAR generator SVG are respectively established in the power system full digital simulation system ADPSS according to actual operating parameters of the wind farm.

[0063] The electromagnetic transient models of the wind power converter and static VAR generator SVG were verified by hardware-in-the-loop (HIL) simulation. The HIL simulation results were compared with the model simulation results under voltage drop / rise faults:

[0064] When the average voltage deviation in the steady-state interval is less than 0.02 and the average voltage deviation in the transient interval is less than 0.05, the verification of the electromagnetic transient model of the wind power converter and the static VAR generator SVG is completed;

[0065] When the average voltage deviation in the steady-state interval is greater than 0.02 or the average voltage deviation in the transient interval is greater than 0.05, the setting parameters of the wind power converter and the static VAR generator SVG in the ADPSS are adjusted, and then the electromagnetic transient models of the wind power converter and the static VAR generator SVG are verified using HIL simulation.

[0066] Calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collection line parameters of the wind farm station.

[0067] The equivalent machine parameters are:

[0068]

[0069] Among them, S eq is the capacity of the equivalent unit, P eq is the equivalent unit active power, Q eq is the equivalent unit reactive power, X m is the magnetizing reactance, R s is the stator resistance, R r is the rotor resistance, X s is the stator reactance, X r is the rotor reactance. i represents the parameters of the i-th unit.

[0070] The axis parameters are:

[0071]

[0072] Among them, H eq is the inertia time constant, K eq is the shaft stiffness coefficient, D eq is the shaft damping coefficient, and i represents the damping coefficient of the i-th wind turbine unit.

[0073] The equivalent box-type transformer parameters are:

[0074]

[0075] Among them, S t is the capacity of a single box transformer, Z t It is the impedance of a single box transformer.

[0076] The calculation process of the collector line parameters is:

[0077] The equivalent impedance of the collector line is determined by the principle of consistent grid connection point loss. The equivalent impedance of the dry-connected collector line is:

[0078]

[0079] The equivalent impedance of the radially connected collector is:

[0080]

[0081] According to the size of the collector line impedance and the power distribution size, the equivalent impedance of the wind power station collector line is:

[0082]

[0083] Among them, Z eq is the equivalent impedance of the collector line, Zi is the impedance of the busbar collector line from the ith unit to the feeder grid connection point, N is the number of equivalent units, X is the average number of units per feeder in the wind power station, and Y is the number of collection lines.

[0084] 2) According to the verified electromagnetic transient model of the wind power converter and static VAR generator SVG and the calculated equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector lines, an equivalent model of the wind farm station is established.

[0085] The wind farm equivalent model is verified by a detailed model, and the HIL simulation results are compared with the model simulation results under voltage drop / swell faults:

[0086] When the average voltage deviation in the steady-state interval is less than 0.02 and the average voltage deviation in the transient interval is less than 0.05, the electromagnetic transient model of the wind power converter and the static VAR generator SVG is verified;

[0087] When the average voltage deviation in the steady-state interval is greater than 0.02 or the average voltage deviation in the transient interval is greater than 0.05, the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector lines are recalculated, and then the accuracy of the equivalent model is verified using the detailed model of the wind farm station.

[0088] A harmonic injection module is introduced into the equivalent model of the wind farm to simulate positive-sequence and negative-sequence oscillation signals.

[0089] Specifically, Bode plots and Nyquist plots are used to assess the broadband oscillation risk of wind farms connected to the power grid.

[0090] Embodiment 2

[0091] This embodiment takes a certain wind farm as an example, and needs to collect actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm.

[0092] According to the actual operating parameters of the wind farm, the electromagnetic transient models of the wind power converter and the static VAR generator SVG are established in the power system full digital simulation system ADPSS, respectively. Figure 2and Figure 3 shown.

[0093] The electromagnetic transient model of the wind power converter and static VAR generator SVG established is verified by hardware-in-the-loop HIL simulation, and the HIL simulation results are compared with the model simulation results under voltage drop / rise fault. The test condition is P = 0.9P n , Q = 0.3Q n 、U=0.5U n , three-phase low penetration 1.214s. The verification results are as follows Figure 4 and Figure 5 As shown, the maximum average voltage deviation in the steady-state interval is 0.014 and the maximum average voltage deviation in the transient interval is 0.032, which are less than the limits of 0.02 and 0.05 respectively. The accuracy verification of the electromagnetic transient model of the wind power converter and the static VAR generator SVG has passed.

[0094] Carry out calculations of equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of wind farm stations.

[0095] Specifically, the equivalent machine parameters are:

[0096]

[0097] Among them, S eq is the capacity of the equivalent unit, P eq is the equivalent unit active power, Q eq is the equivalent unit reactive power, X m is the magnetizing reactance, R s is the stator resistance, R r is the rotor resistance, X s is the stator reactance, X r is the rotor reactance, and i represents the parameters of the i-th unit.

[0098] The axis parameters are:

[0099]

[0100] Among them, H eq is the inertia time constant, K eq is the shaft stiffness coefficient, D eq is the shaft damping coefficient, and i represents the damping coefficient of the i-th wind turbine unit.

[0101] The equivalent box-type transformer parameters are:

[0102]

[0103] Among them, S t is the capacity of a single box transformer, Z t It is the impedance of a single box transformer.

[0104] The calculation process of the collector line parameters is:

[0105] The equivalent impedance of the collector line is determined by the principle of consistent grid connection point loss. The equivalent impedance of the dry-connected collector line is:

[0106]

[0107] The equivalent impedance of the radially connected collector is:

[0108]

[0109] According to the size of the collector line impedance and the power distribution size grouping, the equivalent impedance of the wind power station collector line is:

[0110]

[0111] Among them, Z eq is the equivalent impedance of the collector line, Zi is the impedance of the busbar collector line from the ith unit to the feeder grid connection point, N is the number of equivalent units, X is the average number of units per feeder in the wind power station, and Y is the number of collection lines.

[0112] According to the electromagnetic transient model of the verified wind power converter and static VAR generator SVG and the calculated equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector lines, an equivalent model of the wind farm station is established, such as Figure 6 shown.

[0113] The established wind farm station equivalent model is verified by the detailed model, and the HIL simulation results are compared with the model simulation results under voltage sag / swell faults.

[0114] The test condition is: the voltage drop depth is selected as 0.8U n 、0.5U n 、0.6U n , 0.2U n , the voltage lifting height is selected as 1.15U n , 1.25U n , 1.3U n , the fault type is three-phase short circuit, and the active power is set to 0.9P n , 0.7P n , 0.2P n , reactive power is set to 0.3Q n , 0.1Q n , 0 and -0.1Q n , the verification results are as follows Figure 7As shown, the maximum average voltage deviation in the steady-state interval is 0.0034 and the maximum average voltage deviation in the transient interval is 0.036, which are less than the limit values ​​of 0.02 and 0.05 respectively. The accuracy verification of the equivalent model of the wind farm station has passed.

[0115] A harmonic injection module is introduced into the wind farm equivalent model based on ADPSS to simulate positive and negative sequence oscillation signals. The topology of the harmonic injection module is as follows: Figure 8 shown.

[0116] Specifically, Bode plots and Nyquist plots are used to assess the broadband oscillation risk of wind farms connected to the power grid.

[0117] Under the positive sequence signal, Fig. 9 As shown in the figure, the impedance Bode diagram under the conditions of 100% active output of the photovoltaic power station, full reactive power of the photovoltaic power station, and maximum capacitive reactive power of SVG shows that in the frequency band of 2.5-1000Hz, the positive-sequence impedance amplitude-frequency curve of the photovoltaic power station intersects with the positive-sequence impedance amplitude-frequency curve of the power grid at the frequency points of 95Hz, 230Hz, and 770Hz, and the phase margin is 87.7°, 128.1°, and 162.8°. The system amplitude / phase stability margin is sufficient, and there is no oscillation risk. Further analysis of the Nyquist curve of the ratio of the positive-sequence impedance of the power grid to the positive-sequence impedance of the photovoltaic power station in the complex plane shows that the positive-sequence Nyquist curve does not enter the prohibited area in the frequency band of 2.5-1000Hz, and the system amplitude margin and phase margin are sufficient, and there is no oscillation risk.

[0118] Under negative sequence signal, such as Fig.10 As shown in the figure, within the frequency band of 2.5-1000Hz, the amplitude-frequency curve of the negative-sequence impedance of the photovoltaic power station and the amplitude-frequency curve of the negative-sequence impedance of the power grid intersect at the frequency points of 240Hz and 780Hz, and the phase margin is 129.2° and 152.8°, and the system amplitude / phase stability margin is sufficient, and there is also no oscillation risk. Further analysis of the Nyquist curve of the ratio of the negative-sequence impedance of the power grid to the negative-sequence impedance of the photovoltaic power station in the complex plane shows that the negative-sequence Nyquist curve does not enter the prohibited area within the frequency band of 2.5-1000Hz, and the system amplitude margin and phase margin are sufficient, and there is no oscillation risk.

[0119] After adding positive-sequence voltage disturbance and negative-sequence voltage disturbance on the high-voltage side of the main transformer of the photovoltaic power station, the photovoltaic power station did not have any oscillation risk in the frequency range of 2.5Hz to 1000Hz. Referring to the Nyquist stability criterion, it was concluded that the photovoltaic power station did not enter the restricted area under any operating conditions, which met the requirements of oscillation risk assessment.

[0120] Embodiment 3

[0121] The broadband oscillation risk assessment system for connecting a wind farm to a power grid according to the present invention comprises:

[0122] The acquisition module is used to collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm station;

[0123] Establishing a module for establishing an electromagnetic transient model of the wind power converter and an electromagnetic transient model of the static VAR generator SVG according to actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm station;

[0124] The calculation module is used to calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station;

[0125] A construction module is used to construct an equivalent model of a wind farm station according to an electromagnetic transient model of a wind power converter and an electromagnetic transient model of a static VAR generator SVG and equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station;

[0126] A simulation module, used for simulating positive sequence and negative sequence oscillation signals according to an equivalent model of the wind farm station;

[0127] The evaluation module is used to evaluate the risk of broadband oscillation of the wind farm station connected to the power grid according to the simulated positive sequence and negative sequence oscillation signals.

[0128] The division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0129] Embodiment 4

[0130] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for assessing the risk of broadband oscillation when a wind farm is connected to a power grid are implemented. The memory may include a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk memory, etc. The processor, the network interface, and the memory are interconnected through an internal bus. The internal bus may be an industrial standard architecture bus, a peripheral component interconnection standard bus, an extended industrial standard structure bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include a program code, and the program code includes computer operation instructions. The memory may include a memory and a non-volatile memory, and provide instructions and data to the processor.

[0131] Embodiment 5

[0132] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for assessing the risk of broadband oscillation when a wind farm is connected to a power grid are implemented. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include a random access memory (RAM) and / or a cache memory, etc. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, etc.

[0133] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0134] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for assessing the broadband oscillation risk of a wind farm connected to a power grid, characterized in that: The following steps are involved: Collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm; According to the actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm station, an electromagnetic transient model of the wind power converter and an electromagnetic transient model of the static VAR generator SVG are established; Calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station; According to the electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG and the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm, an equivalent model of the wind farm is constructed; Simulating positive-sequence and negative-sequence oscillation signals according to an equivalent model of the wind farm station; The risk assessment of broadband oscillation of wind farm access to the power grid is performed based on the simulated positive-sequence and negative-sequence oscillation signals.

2. The method for assessing the risk of broadband oscillation when a wind farm is connected to a power grid according to claim 1, characterized in that: Before constructing the equivalent model of the wind farm according to the electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG and the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm, the equivalent model of the wind farm may also include: The electromagnetic transient model of the wind power converter and the electromagnetic transient model of the static VAR generator SVG are simulated and verified.

3. The method for assessing broadband oscillation risk of wind farms connected to a power grid according to claim 1, characterized in that: The equivalent machine parameters are: Among them, S eq is the capacity of the equivalent unit, P eq is the equivalent unit active power, Q eq is the equivalent unit reactive power, X m is the magnetizing reactance, R s is the stator resistance, R r is the rotor resistance, X s is the stator reactance, X r is the rotor reactance, and i represents the parameters of the i-th unit.

4. The method for assessing broadband oscillation risk of wind farms connected to a power grid according to claim 1, characterized in that: The axis parameters are: Among them, H eq is the inertia time constant, K eq is the shaft stiffness coefficient, D eq is the shaft damping coefficient, and i represents the damping coefficient of the i-th wind turbine unit.

5. The method for assessing broadband oscillation risk of wind farms connected to a power grid according to claim 1, characterized in that: The equivalent box-type transformer parameters are: Among them, S t is the capacity of a single box transformer, Z t It is the impedance of a single box transformer.

6. The method for assessing broadband oscillation risk of wind farms connected to a power grid according to claim 1, characterized in that: The calculation process of the collector line parameters is: The equivalent impedance of the collector line is determined by the principle of consistent grid connection point loss. The equivalent impedance of the dry-connected collector line is: The equivalent impedance of the radially connected collector is: According to the size of the collector line impedance and the power distribution size, the equivalent impedance of the wind power station collector line is: Among them, Z eq is the equivalent impedance of the collector line, Zi is the impedance of the busbar collector line from the ith unit to the feeder grid connection point, N is the number of equivalent units, X is the average number of units per feeder in the wind power station, and Y is the number of collection lines.

7. The method for assessing broadband oscillation risk of wind farms connected to a power grid according to claim 1, characterized in that: The process of performing risk assessment of broadband oscillation of wind farm access to the power grid according to the simulated positive-sequence and negative-sequence oscillation signals is as follows: Introducing harmonic injection module into the equivalent model of wind farm station to simulate positive and negative sequence oscillation signals; Based on the simulated positive-sequence and negative-sequence oscillation signals, the risk of broadband oscillation of wind farms connected to the power grid is assessed using Bode plots and Nyquist plots.

8. A broadband oscillation risk assessment system for wind farm access to a power grid, characterized in that: include: The acquisition module is used to collect the actual operating parameters of the wind power converter and static VAR generator SVG of the wind farm station; Establishing a module for establishing an electromagnetic transient model of the wind power converter and an electromagnetic transient model of the static VAR generator SVG according to actual operating parameters of the wind power converter and the static VAR generator SVG of the wind farm station; The calculation module is used to calculate the equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station; A construction module is used to construct an equivalent model of a wind farm station according to an electromagnetic transient model of a wind power converter and an electromagnetic transient model of a static VAR generator SVG and equivalent machine parameters, shaft system parameters, equivalent box transformer parameters and collector line parameters of the wind farm station; A simulation module, used for simulating positive sequence and negative sequence oscillation signals according to an equivalent model of the wind farm station; The evaluation module is used to evaluate the risk of broadband oscillation of a wind farm station connected to a power grid according to the simulated positive-sequence and negative-sequence oscillation signals.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for assessing the risk of broadband oscillation of a wind farm connected to a power grid as claimed in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for assessing the risk of broadband oscillation of a wind farm connected to a power grid as claimed in any one of claims 1 to 7 are implemented.

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