Resonance overvoltage suppression method and system of land wind power low-frequency alternating current system

Abstract

The invention relates to the technical field of new energy power generation, and discloses a resonance overvoltage suppression method and system for an onshore wind power low-frequency alternating-current system, and the method comprises the steps: firstly, connecting a small reactance to a neutral point of a shunt reactor in the onshore wind power low-frequency alternating-current system, and then, through presetting a neutral point small reactance function, carrying out the resonance overvoltage suppression of the onshore wind power low-frequency alternating-current system; according to the method, the initial neutral point small reactance value of the neutral point small reactance in the land wind power low-frequency alternating-current system can be accurately calculated, then the initial neutral point small reactance value is input into a simulation model of the land wind power low-frequency alternating-current system for overvoltage simulation, and a target neutral point small reactance value meeting a preset standard overvoltage requirement is screened out; and finally, the small reactance of the neutral point in the system is adjusted according to the small reactance value of the target neutral point, so that the suppression effect on the resonance overvoltage of the land wind power low-frequency alternating-current system is realized, and the operation stability of the land wind power low-frequency alternating-current system is improved. The technical problem of how to suppress the power frequency resonance overvoltage of the land wind power low-frequency alternating current system is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy power generation, and in particular to a method and system for suppressing resonant overvoltage in an onshore wind power low-frequency alternating current system. Background Art

[0002] With the continuous growth of electricity demand and the increasing complexity of power systems, traditional power transmission systems have faced many challenges. For example, the high-frequency transmission system used in onshore wind farms has problems such as large transmission losses, high cable costs, and large electrical equipment. In order to solve these problems, onshore wind power low-frequency AC transmission systems have emerged. Low-frequency AC technology can reduce transmission losses, reduce cable costs, reduce the size of electrical equipment, and improve the overall economy and operational reliability of wind farms. However, during the process of wind power grid connection, due to the interaction between wind farms and power grids, resonant overvoltage problems may occur, especially low-frequency resonant overvoltage, which poses a serious threat to the safe and stable operation of the power grid.

[0003] For onshore wind power low-frequency AC transmission systems, the problem of resonant overvoltage is particularly prominent, because wind farms are usually connected to the power grid through long-distance transmission lines. These lines themselves have high capacitance to the ground and are prone to forming resonant loops with other components in the power grid. In the context of low-frequency AC transmission not yet being widely used, how to avoid power frequency resonant overvoltage has become an urgent problem to be solved. Summary of the invention

[0004] The present invention provides a method and system for suppressing resonant overvoltage of an onshore wind power low-frequency AC system, solving the technical problem of how to suppress the power frequency resonant overvoltage of an onshore wind power low-frequency AC system.

[0005] A first aspect of the present invention provides a method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system, comprising:

[0006] In response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained;

[0007] Using the electrical parameters to input a preset neutral point small reactance function, and outputting a plurality of initial neutral point small reactance values;

[0008] Using a plurality of the initial neutral point small reactance values ​​to input the simulation model to perform overvoltage simulation of different types of typical faults, and generating overvoltage simulation results under each of the typical faults;

[0009] Determine whether each overvoltage simulation result meets the preset standard overvoltage requirement;

[0010] If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as the target neutral point small reactance value;

[0011] The reactance parameter of the neutral point small reactance of the onshore wind power low-frequency AC system is adjusted according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

[0012] Optionally, the electrical parameters include reactance values ​​of multiple shunt reactors, a positive-sequence capacitive reactance value of the overhead line, and a zero-sequence capacitive reactance value of the overhead line.

[0013] Optionally, the step of using the electrical parameters to input a preset neutral point small reactance function and outputting a plurality of initial neutral point small reactance values ​​comprises:

[0014] Performing a difference operation using a positive-sequence capacitive reactance value of the overhead line and a zero-sequence capacitive reactance value of the overhead line to obtain a first difference;

[0015] The reactance values ​​of the plurality of parallel reactors are respectively used with a preset small reactance coefficient to obtain a plurality of first multiplication values;

[0016] Using a plurality of the first multiplication values ​​to perform difference operations with the preset small reactance coefficient respectively, to obtain a plurality of second difference values;

[0017] Performing ratio operations on the first difference and the plurality of second difference values ​​to obtain a plurality of first ratios;

[0018] A plurality of the first ratios are respectively used to perform ratio operations with the square values ​​of the reactance values ​​of the associated shunt reactors to obtain a plurality of initial neutral point small reactance values.

[0019] Optionally, the typical fault is any one of a single-phase breaking fault, a two-phase breaking fault, a single-phase grounding fault and a two-phase grounding fault.

[0020] Optionally, the overvoltage simulation result includes a line resonance overvoltage value, a latent supply current and a recovery voltage value.

[0021] Optionally, the preset standard overvoltage requirement is that the line resonance overvoltage value is in a preset standard resonance overvoltage interval, the latent supply current is in a preset standard latent supply current interval, and the recovery voltage value is in a preset recovery voltage interval.

[0022] Optionally, the reactance parameter is the capacity of the parallel capacitor.

[0023] A second aspect of the present invention provides a resonant overvoltage suppression system for an onshore wind power low-frequency AC system, comprising:

[0024] A response module, used to respond to an overvoltage suppression request for an onshore wind power low-frequency AC system, build a simulation model of the onshore wind power low-frequency AC system and obtain associated electrical parameters;

[0025] An initial neutral point small reactance value module is used to use the electrical parameters to input a preset neutral point small reactance function and output a plurality of initial neutral point small reactance values;

[0026] An overvoltage simulation module, used to use a plurality of the initial neutral point small reactance values ​​to input the simulation model to perform overvoltage simulation of different types of typical faults, and generate overvoltage simulation results under each of the typical faults;

[0027] A judgment module is used to judge whether each overvoltage simulation result meets the preset standard overvoltage requirement;

[0028] A target neutral point small reactance value module is used to use the initial neutral point small reactance value associated with the overvoltage simulation result as the target neutral point small reactance value if the overvoltage simulation result meets the preset standard overvoltage requirement;

[0029] The adjustment module is used to adjust the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

[0030] A third aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system as described in any one of the above items.

[0031] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, the method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system as described in any one of the above items is implemented.

[0032] It can be seen from the above technical solutions that the present invention has the following advantages:

[0033] In the present invention, in response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained, the electrical parameters are used to input a preset neutral point small reactance function, a plurality of initial neutral point small reactance values ​​are output, and a plurality of initial neutral point small reactance values ​​are used to input the simulation model to perform overvoltage simulations of different types of typical faults, and overvoltage simulation results under each typical fault are generated, and it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement. If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as a target neutral point small reactance value, and the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system are adjusted according to the target neutral point small reactance value until the overhead line in the onshore wind power low-frequency AC system is The overvoltage value of the line is in a preset standard overvoltage range. The present invention first connects a small reactance to the neutral point of the shunt reactor in the onshore wind power low-frequency AC system, and then accurately calculates the initial neutral point small reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system through a preset neutral point small reactance function. Secondly, the initial neutral point small reactance value is input into a simulation model of the onshore wind power low-frequency AC system to perform overvoltage simulation, and a target neutral point small reactance value that meets the preset standard overvoltage requirement is screened out. Finally, the neutral point small reactance in the system is adjusted according to the target neutral point small reactance value, thereby achieving the effect of suppressing the resonant overvoltage of the onshore wind power low-frequency AC system, improving the operating stability of the onshore wind power low-frequency AC system, and solving the technical problem of how to suppress the power frequency resonant overvoltage of the onshore wind power low-frequency AC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative labor.

[0035] Figure 1 A flowchart of a method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system provided in Embodiment 1 of the present invention;

[0036] Figure 2 A flowchart of a method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system provided in Embodiment 2 of the present invention;

[0037] Figure 3 It is the overall topology diagram of the onshore wind power low-frequency AC system;

[0038] Figure 4 It is a schematic diagram of the single-phase breaking equivalent circuit of the shunt reactor without the small reactor connected;

[0039] Figure 5 It is a schematic diagram of the two-phase breaking equivalent circuit of the shunt reactor without the small reactance connected;

[0040] Figure 6 It is a schematic diagram of the single-phase breaking equivalent circuit of a shunt reactor connected to a small reactance;

[0041] Figure 7 It is a schematic diagram of the two-phase breaking equivalent circuit of a shunt reactor connected to a small reactance;

[0042] Figure 8 A structural block diagram of a resonant overvoltage suppression system for an onshore wind power low-frequency AC system provided in Embodiment 3 of the present invention;

[0043] Fig. 9 This is a structural block diagram of a computer device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0044] The embodiments of the present invention provide a method and system for suppressing resonant overvoltage of an onshore wind power low-frequency AC system, which are used to solve the technical problem of how to suppress the power frequency resonant overvoltage of an onshore wind power low-frequency AC system.

[0045] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] See also Figure 1 , Figure 1 A flowchart of the steps of a method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system provided in Embodiment 1 of the present invention.

[0047] The present invention provides a method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system, comprising:

[0048] Step 101: In response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is built and associated electrical parameters are obtained.

[0049] An overvoltage suppression request refers to a request instruction to control and reduce the overvoltage in the onshore wind power low-frequency AC system in order to ensure the safe and stable operation of the system.

[0050] The simulation model refers to a simulation model for overvoltage simulation generated by modeling the topological structure of each unit in the onshore wind power low-frequency AC system.

[0051] The electrical parameters refer to the calculation parameters used to input a preset neutral point small reactance function and calculate the reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system.

[0052] In an embodiment of the present invention, in response to a request instruction for controlling and reducing overvoltage occurring in an onshore wind power low-frequency AC system, the request instruction is read, model parameters for constructing a simulation model are obtained to construct the simulation model, and electrical parameters of the onshore wind power low-frequency AC system are obtained.

[0053] It is worth mentioning that the model parameters include but are not limited to wind turbine related parameters (such as generator parameters and wind rotor parameters, etc.), transmission line related parameters (such as overhead line length, conductor model, positive sequence resistance, positive sequence inductance and positive sequence capacitance, etc.), fault and disturbance related parameters (such as fault location, fault resistance size, etc.).

[0054] Step 102: Use electrical parameters to input a preset neutral point small reactance function, and output a plurality of initial neutral point small reactance values.

[0055] The preset neutral point small reactance function refers to a calculation function used to calculate the reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system.

[0056] The initial neutral point small reactance value refers to the reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system obtained by calculation based on electrical parameters.

[0057] In the embodiment of the present invention, the preset neutral point small reactance function is calculated by using electrical parameters as input, and a plurality of initial neutral point small reactance values ​​are output.

[0058] Step 103: Use multiple initial neutral point small reactance values ​​to input the simulation model to perform overvoltage simulation of different types of typical faults, and generate overvoltage simulation results under each typical fault.

[0059] Overvoltage simulation refers to the process of using simulation software to simulate the overvoltage phenomena that may occur in onshore wind power low-frequency AC systems.

[0060] A typical fault refers to an electrical or mechanical fault that will affect the normal operation of the onshore wind power low-frequency AC system, reduce power generation efficiency, and may even damage the equipment.

[0061] The overvoltage simulation result refers to the simulation of the overvoltage phenomenon of the onshore wind power low-frequency AC system, and the simulation result of the onshore wind power low-frequency AC system under typical faults.

[0062] In an embodiment of the present invention, multiple initial neutral point small reactance values ​​are input into a simulation model to perform overvoltage simulation of different types of typical faults, and overvoltage simulation results corresponding to multiple initial neutral point small reactance values ​​under each typical fault are generated.

[0063] Step 104 : determining whether each overvoltage simulation result meets a preset standard overvoltage requirement.

[0064] The preset standard overvoltage requirement refers to a requirement for judging whether an overvoltage simulation result has achieved the effect of suppressing the resonant overvoltage.

[0065] In the embodiment of the present invention, it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement.

[0066] Step 105: If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as the target neutral point small reactance value.

[0067] The target neutral point small reactance value refers to the initial neutral point small reactance value associated with the overvoltage simulation result that meets the preset standard overvoltage requirements as the optimal neutral point small reactance value, which is used to control the increase in the non-fault phase voltage, ensure that the non-fault phase voltage of the system is within the range that the equipment insulation can withstand during the fault, and improve the transient stability of the system.

[0068] In an embodiment of the present invention, if the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result meeting the preset standard overvoltage requirement is used as the target neutral point small reactance value.

[0069] Step 106: adjust the reactance parameter of the neutral point small reactance of the onshore wind power low-frequency AC system according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

[0070] The reactance parameter refers to the capacity of the parallel capacitor.

[0071] The preset standard overvoltage interval refers to a pre-set voltage range. Overvoltages within this range are considered acceptable to the onshore wind power low-frequency AC system, will not cause unacceptable damage to the equipment in the onshore wind power low-frequency AC system, and can ensure the safe, stable and reliable operation of the onshore wind power low-frequency AC system.

[0072] It is worth mentioning that the upper and lower limits of the preset standard overvoltage range are determined according to the actual situation of the onshore wind power low-frequency AC system, which will not be elaborated here.

[0073] It should be noted that the effect of the small neutral reactance is interrelated with the parameters of other components in the onshore wind power low-frequency AC system. The equivalent adjustment of the small neutral reactance can be achieved by adjusting the parameters of other related components. There are parallel capacitors in the onshore wind power low-frequency AC system that affect the resonance characteristics of the onshore wind power low-frequency AC system together with the small neutral reactance. Therefore, by changing the capacity of the parallel capacitors in the onshore wind power low-frequency AC system, the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is affected. Specifically, when the optimal target small neutral reactance value is obtained by overvoltage simulation, the capacity of the parallel capacitor is reduced according to the preset gradient according to the optimal target small neutral reactance value, so that the capacitance-inductance relationship of the onshore wind power low-frequency AC system changes, thereby adjusting the overvoltage value of the overhead line in the onshore wind power low-frequency AC system.

[0074] In an embodiment of the present invention, the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system are adjusted according to a preset gradient based on the target neutral point small reactance value, so that the capacitance-inductance relationship of the onshore wind power low-frequency AC system changes, and then the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is adjusted to be within a preset standard overvoltage range.

[0075] In the present invention, in response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained, the electrical parameters are used to input a preset neutral point small reactance function, a plurality of initial neutral point small reactance values ​​are output, and a plurality of initial neutral point small reactance values ​​are used to input the simulation model to perform overvoltage simulations of different types of typical faults, and overvoltage simulation results under each typical fault are generated, and it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement. If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as a target neutral point small reactance value, and the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system are adjusted according to the target neutral point small reactance value until the overhead line in the onshore wind power low-frequency AC system is The overvoltage value of the line is in a preset standard overvoltage range. The present invention first connects a small reactance to the neutral point of the shunt reactor in the onshore wind power low-frequency AC system, and then accurately calculates the initial neutral point small reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system through a preset neutral point small reactance function. Secondly, the initial neutral point small reactance value is input into a simulation model of the onshore wind power low-frequency AC system to perform overvoltage simulation, and a target neutral point small reactance value that meets the preset standard overvoltage requirement is screened out. Finally, the neutral point small reactance in the system is adjusted according to the target neutral point small reactance value, thereby achieving the effect of suppressing the resonant overvoltage of the onshore wind power low-frequency AC system, improving the operating stability of the onshore wind power low-frequency AC system, and solving the technical problem of how to suppress the power frequency resonant overvoltage of the onshore wind power low-frequency AC system.

[0076] See also Figure 2 , Figure 2 A flowchart of the steps of a method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system provided in Embodiment 2 of the present invention.

[0077] The present invention provides a method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system, comprising:

[0078] Step 201: In response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed.

[0079] See also Figure 3 , Figure 3 It is the overall topology diagram of the onshore wind power low-frequency AC system;

[0080] The onshore wind power low-frequency AC system includes a wind turbine module, a collector cable module, a low-frequency boost module, a shunt reactor module, an overhead line module, a converter module and an equivalent power supply module which are arranged in sequence;

[0081] Wind turbine module: This module simulates the entire process of wind turbine conversion from wind energy to electrical energy in detail, including motor type, transformer and its control strategy, so that the model can be flexibly adjusted to adapt to different wind conditions and grid requirements.

[0082] Collector cable module: This module is responsible for collecting the power generated by multiple wind turbines and transmitting it to the low-frequency boost module. By adjusting the voltage level, cross-sectional electrical parameters and length of the cable, the power transmission efficiency can be optimized and the loss can be reduced.

[0083] Low-frequency boost module: A low-frequency transformer is used to boost the electric energy transmitted by the collector cable to reduce transmission losses and facilitate long-distance transmission. The transformer parameters of this module (such as primary and secondary voltages, short-circuit impedance) are adjustable to meet different system requirements.

[0084] Shunt reactor module: Installed on overhead lines, it is used to limit power frequency overvoltage and help protect electrical equipment in the power system.

[0085] Overhead line module: simulates the electrical characteristics and transmission environment of overhead lines, including conductor parameters, line length, transposition method and tower structure, etc. These parameters are adjustable to ensure stable transmission of power to the centralized control center.

[0086] Converter module: It uses advanced M3C converter technology to convert low-frequency AC power into industrial frequency AC power, improving the flexibility and efficiency of the system's access to the power grid.

[0087] Equivalent power supply module: simulates the power supply characteristics of the large power grid, provides stable power support for the entire system, and ensures the stability and reliability of system operation.

[0088] In the embodiment of the present invention, PSCAD software is used to perform modular modeling on the onshore wind power low-frequency AC system to construct a simulation model.

[0089] Among them, the construction of the simulation model:

[0090] Determine system structure and parameters: clarify the overall architecture of the wind power low-frequency AC system, including wind turbine type, converter type, transformer, overhead lines, and possible filters and protection equipment, etc., collect and determine the detailed technical parameters of all equipment, such as rated power, rated voltage, reactance value, etc.

[0091] Build a simulation environment: Add various modules (such as generators, converters, lines, loads, etc.) to the simulation environment and set the corresponding parameters. After completing the initialization of each module, a complete onshore wind power low-frequency AC system simulation model is formed.

[0092] The settings for modular modeling using PSCAD software are as follows:

[0093] The wind turbine module settings include:

[0094] Rated reference power: set to any value between 5-18MW, adjusted according to specific project requirements.

[0095] Output voltage: depends on the type of wind turbine and the voltage level of the collector cable.

[0096] Frequency: Select 20Hz, 30Hz or 50 / 3Hz, depending on the low frequency design requirements of the system.

[0097] Fan step-up transformation ratio: Select the appropriate transformation ratio according to the fan outlet voltage and the collector cable voltage level, such as 0.69 / 35kV, 1.14 / 35kV, etc.

[0098] The collector cable module setup includes:

[0099] Electrical parameters: including outer diameter, inner diameter, conductor diameter, insulation thickness, sheath thickness, etc. These parameters need to be set according to the actual cable specifications.

[0100] Voltage level: Select 35kV or 66kV to match the wind turbine step-up transformer output.

[0101] Line length: Set according to the actual cable length in the project.

[0102] The low frequency boost module settings include:

[0103] Transformer parameters: Set the primary and secondary voltages, as well as the short-circuit impedance. The transformation ratio is determined according to the voltage level of the collector cable and overhead line, such as 35 / 220kV, 66 / 330kV, etc.

[0104] Short Circuit Impedance: Adjustable within the range of 0.05-0.25 to optimize transformer performance.

[0105] The shunt reactor module setup includes:

[0106] Rated voltage parameters: The rated voltage of the neutral point small reactor is determined based on the compensation degree of the shunt reactor and the maximum power frequency overvoltage value that may occur at the neutral point.

[0107] The Overhead Line Module Setup includes:

[0108] Electrical parameters: including resistance per unit length, conductor diameter, etc., are set according to actual line parameters.

[0109] Line length: Set according to the line length in the actual project.

[0110] Transposition and tower structure: Select the corresponding module in the simulation software for setting and use the Bergeron model for simulation.

[0111] The inverter module setup includes:

[0112] M3C parameters: Set the number of bridge arm submodules, submodule capacitance value, bridge arm reactor inductance value and module capacitance voltage average value. These parameters need to be adjusted according to the converter design requirements and system requirements.

[0113] The equivalent power module setup includes:

[0114] Power supply parameters: Set the voltage amplitude and phase angle to simulate the power supply characteristics of the large power grid. The voltage amplitude is used to specify the voltage level of the equivalent power supply, and the phase angle is used to simulate the phase difference between the nodes in the power grid.

[0115] Internal impedance: Set the positive-sequence impedance and zero-sequence impedance to reflect the impedance characteristics of the power grid.

[0116] Step 202: Obtain electrical parameters associated with the onshore wind power low-frequency AC system.

[0117] Furthermore, the electrical parameters include reactance values ​​of a plurality of shunt reactors, a positive-sequence capacitive reactance value of the overhead line, and a zero-sequence capacitive reactance value of the overhead line.

[0118] In an embodiment of the present invention, reactance values ​​of a plurality of shunt reactors associated with an onshore wind power low-frequency AC system, a positive-sequence capacitive reactance value of an overhead line, and a zero-sequence capacitive reactance value of an overhead line are obtained.

[0119] Step 203: Use electrical parameters to input a preset neutral point small reactance function, and output a plurality of initial neutral point small reactance values.

[0120] It is worth mentioning that the preset neutral point small reactance function is a pre-set neutral point small reactance value calculation function in the simulation model. Electrical parameters are added in the simulation environment, and the preset neutral point small reactance function is input to calculate the reactance value of the neutral point small reactance, and then overvoltage simulation of typical faults is performed in the simulation model.

[0121] Further, step 203 may include the following sub-steps:

[0122] S11. Perform a difference operation using the positive-sequence capacitive reactance value of the overhead line and the zero-sequence capacitive reactance value of the overhead line to obtain a first difference.

[0123] S12, using the reactance values ​​of multiple parallel reactors and the preset small reactance coefficient to obtain multiple first multiplication values.

[0124] S13, using a plurality of first product values ​​to perform difference operations with preset small reactance coefficients respectively to obtain a plurality of second difference values.

[0125] S14. Perform ratio operations on the first difference value with the multiple second difference values ​​to obtain multiple first ratios.

[0126] S15. Perform ratio operations on the multiple first ratios and the square values ​​of the reactance values ​​of the associated parallel reactors to obtain multiple initial neutral point small reactance values.

[0127] For ease of understanding, in a specific implementation, to facilitate the implementation of the method, the above process can be converted into a formula encapsulation form, wherein the calculation method of the initial neutral point small reactance value can be as follows:

[0128]

[0129] In the formula, Indicates the initial neutral point minimum reactance value, Indicates the reactance value of the shunt reactor, Indicates the positive sequence capacitive reactance of the overhead line, Indicates the zero-sequence capacitive reactance of the overhead line, Represents a preset small reactance coefficient, wherein the preset small reactance coefficient is preferably 3.

[0130] In an embodiment of the present invention, the reactance values ​​of multiple parallel reactors, the positive-sequence capacitive reactance value of the overhead line and the zero-sequence capacitive reactance value of the overhead line are input into a preset neutral point small reactance function for calculation, and an initial neutral point small reactance value associated with the reactance values ​​of the multiple parallel reactors can be output. That is, each time the reactance value of a parallel reactor, a positive-sequence capacitive reactance value of the overhead line and a zero-sequence capacitive reactance value of the overhead line are input into the preset neutral point small reactance function, an initial neutral point small reactance value can be output.

[0131] Step 204 , using a plurality of initial neutral point small reactance values ​​to input a simulation model to perform overvoltage simulations for different types of typical faults, and generating overvoltage simulation results for each typical fault.

[0132] Further, the typical fault is any one of a single-phase breaking fault, a two-phase breaking fault, a single-phase grounding fault and a two-phase grounding fault.

[0133] It is worth mentioning that the simulation model in the present invention is provided with an automatic fault setting module, which can set the single-phase disconnection, two-phase disconnection, single-phase grounding and two-phase grounding faults on both sides of the line (overhead line fan side and converter side) with one click. At the same time, the corresponding line resonant overvoltage value, latent supply current and recovery voltage value under different faults are output. As well as the optimal neutral point small reactance value obtained by the preset neutral point small reactance function of the neutral point small reactance, the small reactance parameters are adjusted to ensure that its suppression effect on the resonant overvoltage meets the design requirements, and the reactance value is fine-tuned according to the simulation results. At the same time, this module can also output the overvoltage value on the neutral point small reactance under different faults, providing reference support for the insulation level of the neutral point small reactance.

[0134] In the embodiment of the present invention, the typical fault is any one of a single-phase breaking fault, a two-phase breaking fault, a single-phase grounding fault, and a two-phase grounding fault on the overhead line wind turbine side and the converter side.

[0135] By setting single-phase breaking fault and two-phase breaking fault on the overhead line wind turbine side and the converter side respectively, extreme conditions that may occur in actual operation are simulated to evaluate the system's fault resistance and resonant overvoltage level.

[0136] See also Figure 4-Figure 7 , Figure 4 It is a schematic diagram of the single-phase breaking equivalent circuit of the shunt reactor without the small reactor connected;

[0137] Figure 5 It is a schematic diagram of the two-phase breaking equivalent circuit of the shunt reactor without the small reactance connected;

[0138] Figure 6 It is a schematic diagram of the single-phase breaking equivalent circuit of a shunt reactor connected to a small reactance;

[0139] Figure 7 This is a schematic diagram of the two-phase breaking equivalent circuit of a shunt reactor connected to a small reactance.

[0140] When the low-frequency overhead line is not in full-phase operation, the disconnected phase may obtain an induced voltage through the phase-to-phase coupling of the live phase. If a shunt reactor is installed on the overhead line, the impedance of the disconnected phase to the ground may be inductive, and the phase-to-phase impedance is capacitive. In this case, power frequency series resonance is likely to occur, resulting in an increase in the loop current, thereby generating a very high power frequency resonance overvoltage on the disconnected phase. Its equivalent circuit is as follows Figure 4-Figure 5 shown.

[0141] Figure 4-Figure 5 Medium X L0 is the inductive reactance of the shunt reactor to ground, X C0 To disconnect the relative capacitance, X C12 To disconnect the relatively healthy phase capacitive reactance, U h To disconnect the induced voltage on the phase, U A is the equivalent potential of the power supply. Figure 4-Figure 5 In the circuit shown, under certain parameter matching conditions, power frequency series resonance may occur, resulting in a large loop current and a high power frequency resonance overvoltage U on the disconnected phase. h .

[0142] In order to limit this resonant overvoltage, the present invention proposes a method of connecting a small reactance at the neutral point of the shunt reactor (called secondary compensation). Its equivalent circuit is as follows: Figure 6-Figure 7 shown. Figure 6-Figure 7 Medium X L12 To disconnect the relatively healthy inductive reactance between phases. This method can compensate for the phase capacitance and increase the phase impedance. By selecting a suitable neutral point small reactance value, parallel resonance can occur between phases. At this time, the phase impedance is close to infinity, so that the power supply voltage is mainly applied to the phase impedance, and the power frequency induced voltage on the disconnected phase is very small, close to zero.

[0143] Step 205: Determine whether each overvoltage simulation result meets a preset standard overvoltage requirement.

[0144] Furthermore, the overvoltage simulation results include line resonance overvoltage value, latent supply current and recovery voltage value.

[0145] Line resonance overvoltage value refers to the voltage amplitude higher than the normal operating voltage caused by the resonance phenomenon of inductance and capacitance components in the line under specific conditions;

[0146] Submerged supply current refers to the current provided to the fault point by the non-fault phase through the phase-to-phase capacitance and mutual inductance after the circuit breakers on both sides of the fault phase trip when a single-phase grounding fault occurs in the line;

[0147] The recovery voltage value refers to the voltage that appears at both ends of the arc gap after the arc in the circuit is extinguished;

[0148] It should be noted that, according to the resonant overvoltage value obtained by simulation, the suppression effect of the resonant overvoltage is ensured to meet the preset standard overvoltage requirements, and the reactance value is fine-tuned according to the simulation results. According to the parameters such as the submerged current and recovery voltage obtained by simulation, check whether the parameters of the small reactance are reasonable and whether it is helpful to quickly restore the normal operation of the line.

[0149] In the embodiment of the present invention, it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement.

[0150] Step 206: If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as the target neutral point small reactance value.

[0151] Furthermore, the preset standard overvoltage requirements are that the line resonant overvoltage value is within a preset standard resonant overvoltage interval, the latent supply current is within a preset standard latent supply current interval, and the recovery voltage value is within a preset recovery voltage interval.

[0152] In an embodiment of the present invention, multiple initial neutral point small reactance values ​​are input into a simulation model to perform overvoltage simulation of different types of typical faults, and line resonant overvoltage values, latent supply currents and recovery voltage values ​​corresponding to different initial neutral point small reactance values ​​under each typical fault are obtained. If the line resonant overvoltage value is in a preset standard resonant overvoltage range, the latent supply current is in a preset standard latent supply current range and the recovery voltage value is in a preset recovery voltage range, the initial neutral point small reactance value associated with the overvoltage simulation result is used as the target neutral point small reactance value.

[0153] Step 207: adjust the reactance parameter of the neutral point small reactance of the onshore wind power low-frequency AC system according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

[0154] Furthermore, the reactance parameter is the capacity of the parallel capacitor.

[0155] In an embodiment of the present invention, the capacity of the parallel capacitor of the neutral point small reactance of the onshore wind power low-frequency AC system is adjusted according to the target neutral point small reactance value, so that the capacitance-inductance relationship of the onshore wind power low-frequency AC system changes, and then the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is adjusted until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is in a preset standard overvoltage range.

[0156] Furthermore, in the actual resonant overvoltage suppression process, the target neutral point small reactance value needs to be substituted into the simulation model for simulation verification to ensure that its suppression effect on the resonant overvoltage meets the requirements. If necessary, the reactance value can be fine-tuned according to the simulation results. Through the above steps, a modular model of the wind power low-frequency AC system can be successfully established in the PSCAD software, and the calculated neutral point small reactance value can be substituted into the system model for simulation verification, and the small reactance resistance value can be fine-tuned to achieve the suppression effect on the resonant overvoltage.

[0157] It is worth mentioning that the resonant overvoltage suppression method of the present invention not only realizes the accurate simulation of the onshore wind power low-frequency AC system through modular modeling, but also effectively solves the power frequency resonant overvoltage problem through targeted resonance suppression measures (connecting a small reactance to the neutral point of the parallel reactor), and builds a neutral point small reactance calculation to realize the one-click generation of the neutral point small reactance. This method is of great significance for improving the safety and stability of onshore wind power low-frequency AC systems, especially under complex working conditions such as non-full-phase operation of low-frequency overhead lines, and can significantly reduce system failure rate and maintenance costs.

[0158] Module advantages:

[0159] 1. Improve simulation efficiency:

[0160] Through one-click fault setting, the time for manual fault setting is greatly reduced.

[0161] Automatically output key electrical parameters and optimized reactance values ​​to improve the efficiency and accuracy of simulation analysis.

[0162] 2. Enhance system stability:

[0163] The optimized target neutral point minimum reactance value helps to reduce the resonant overvoltage and improve the stability of the power system.

[0164] Providing reference support for the small reactance insulation level of the neutral point helps ensure safe operation of the equipment.

[0165] 3. Improve engineering application value:

[0166] The module can simulate a variety of fault conditions and provide strong support for power system fault analysis and protection strategy formulation.

[0167] The optimized target neutral point minimum reactance value can be directly applied in practical projects to improve the reliability and safety of the power system.

[0168] It should be noted that the resonant overvoltage suppression method of the onshore wind power low-frequency AC system of the present invention effectively solves the power frequency resonant overvoltage problem that may occur in the onshore wind power low-frequency AC system through detailed modular modeling and targeted resonance suppression measures, and can be used as a reference for modeling all types of single-ended converter onshore wind power low-frequency AC systems.

[0169] Accurately simulate the single-phase and two-phase disconnection fault states of the line when the system is not in full-phase operation, observe and record the resonant overvoltage level of the system under different fault conditions, adjust the small neutral reactance parameters to achieve the level of suppressing the resonant overvoltage, and in principle meet the requirements of suppressing the power frequency resonant overvoltage, try to select a smaller resistance value to reduce the insulation level and cost. If modifying the small neutral reactance parameters cannot limit the resonant overvoltage value, then choose to modify the high-resistance parameters for simulation until the system resonant overvoltage level does not exceed the maximum withstand voltage of the protection equipment.

[0170] In the present invention, in response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained, the electrical parameters are used to input a preset neutral point small reactance function, a plurality of initial neutral point small reactance values ​​are output, and a plurality of initial neutral point small reactance values ​​are used to input the simulation model to perform overvoltage simulations of different types of typical faults, and overvoltage simulation results under each typical fault are generated, and it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement. If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as a target neutral point small reactance value, and the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system are adjusted according to the target neutral point small reactance value until the overhead line in the onshore wind power low-frequency AC system is The overvoltage value of the line is in a preset standard overvoltage range. The present invention first connects a small reactance to the neutral point of the shunt reactor in the onshore wind power low-frequency AC system, and then accurately calculates the initial neutral point small reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system through a preset neutral point small reactance function. Secondly, the initial neutral point small reactance value is input into a simulation model of the onshore wind power low-frequency AC system to perform overvoltage simulation, and a target neutral point small reactance value that meets the preset standard overvoltage requirement is screened out. Finally, the neutral point small reactance in the system is adjusted according to the target neutral point small reactance value, thereby achieving the effect of suppressing the resonant overvoltage of the onshore wind power low-frequency AC system, improving the operating stability of the onshore wind power low-frequency AC system, and solving the technical problem of how to suppress the power frequency resonant overvoltage of the onshore wind power low-frequency AC system.

[0171] See also Figure 8 , Figure 8 This is a structural block diagram of a resonant overvoltage suppression system for an onshore wind power low-frequency AC system provided in Embodiment 3 of the present invention.

[0172] The present invention provides a resonant overvoltage suppression system for an onshore wind power low-frequency AC system, comprising:

[0173] A response module 301 is used to respond to an overvoltage suppression request for an onshore wind power low-frequency AC system, build a simulation model of the onshore wind power low-frequency AC system and obtain associated electrical parameters;

[0174] An initial neutral point small reactance value module 302 is used to input a preset neutral point small reactance function using electrical parameters and output a plurality of initial neutral point small reactance values;

[0175] An overvoltage simulation module 303 is used to use a plurality of initial neutral point small reactance values ​​to input a simulation model to perform overvoltage simulation of different types of typical faults, and generate overvoltage simulation results under each typical fault;

[0176] A judgment module 304 is used to judge whether each overvoltage simulation result meets a preset standard overvoltage requirement;

[0177] A target neutral point small reactance value module 305 is used to use the initial neutral point small reactance value associated with the overvoltage simulation result as the target neutral point small reactance value if the overvoltage simulation result meets the preset standard overvoltage requirement;

[0178] The adjustment module 306 is used to adjust the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

[0179] Furthermore, the electrical parameters include reactance values ​​of a plurality of shunt reactors, a positive-sequence capacitive reactance value of the overhead line, and a zero-sequence capacitive reactance value of the overhead line.

[0180] Further, the initial neutral point small reactance value module 302 includes:

[0181] A first difference submodule, configured to perform a difference operation using a positive sequence capacitance value of the overhead line and a zero sequence capacitance value of the overhead line to obtain a first difference value;

[0182] A first multiplication submodule is used to obtain a plurality of first multiplication values ​​by respectively using the reactance values ​​of a plurality of parallel reactors and a preset small reactance coefficient;

[0183] A second difference submodule is used to use the multiple first product values ​​to perform difference operations with the preset small reactance coefficient respectively to obtain multiple second difference values;

[0184] A first ratio submodule, configured to perform ratio operations on the first difference value with the plurality of second difference values ​​to obtain a plurality of first ratio values;

[0185] The data output submodule is used to perform ratio operations on the multiple first ratios and the square values ​​of the reactance values ​​of the associated shunt reactors to obtain multiple initial neutral point small reactance values.

[0186] Further, the typical fault is any one of a single-phase breaking fault, a two-phase breaking fault, a single-phase grounding fault and a two-phase grounding fault.

[0187] Furthermore, the overvoltage simulation results include line resonance overvoltage value, latent supply current and recovery voltage value.

[0188] Furthermore, the preset standard overvoltage requirements are that the line resonant overvoltage value is within a preset standard resonant overvoltage interval, the latent supply current is within a preset standard latent supply current interval, and the recovery voltage value is within a preset recovery voltage interval.

[0189] Furthermore, the reactance parameter is the capacity of the parallel capacitor.

[0190] In the present invention, in response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained, the electrical parameters are used to input a preset neutral point small reactance function, a plurality of initial neutral point small reactance values ​​are output, and a plurality of initial neutral point small reactance values ​​are used to input the simulation model to perform overvoltage simulations of different types of typical faults, and overvoltage simulation results under each typical fault are generated, and it is determined whether each overvoltage simulation result meets a preset standard overvoltage requirement. If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as a target neutral point small reactance value, and the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system are adjusted according to the target neutral point small reactance value until the overhead line in the onshore wind power low-frequency AC system is The overvoltage value of the line is in a preset standard overvoltage range. The present invention first connects a small reactance to the neutral point of the shunt reactor in the onshore wind power low-frequency AC system, and then accurately calculates the initial neutral point small reactance value of the neutral point small reactance in the onshore wind power low-frequency AC system through a preset neutral point small reactance function. Secondly, the initial neutral point small reactance value is input into a simulation model of the onshore wind power low-frequency AC system to perform overvoltage simulation, and a target neutral point small reactance value that meets the preset standard overvoltage requirement is screened out. Finally, the neutral point small reactance in the system is adjusted according to the target neutral point small reactance value, thereby achieving the effect of suppressing the resonant overvoltage of the onshore wind power low-frequency AC system, improving the operating stability of the onshore wind power low-frequency AC system, and solving the technical problem of how to suppress the power frequency resonant overvoltage of the onshore wind power low-frequency AC system.

[0191] See also Fig. 9 , Fig. 9 This is a structural block diagram of a computer device provided in Embodiment 4 of the present invention.

[0192] An electronic device according to an embodiment of the present invention includes: a memory 401 and a processor 402, wherein the memory 402 stores a computer program; when the computer program is executed by the processor 402, the processor 402 executes a resonant overvoltage suppression method for an onshore wind power low-frequency AC system according to any of the above embodiments.

[0193] The memory 401 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read-only memory), an EPROM, a hard disk or a ROM. The memory 401 has a storage space 403 for a program code 413 for executing any method step in the above method. For example, the storage space 403 for the program code may include individual program codes 413 for implementing the various steps in the above method, respectively. These program codes may be read from or written to one or more computer program products. These computer program products include program code carriers such as hard disks, compact disks (CDs), memory cards or floppy disks. The program code may be compressed, for example, in an appropriate form. When these codes are run by a computing and processing device, the computing and processing device performs the various steps in the method described above. These program codes may be read from or written to one or more computer program products. These computer program products include program code carriers such as hard disks, compact disks (CDs), memory cards or floppy disks. The program code may be compressed, for example, in an appropriate form. When these codes are executed by a computing and processing device, the computing and processing device is caused to execute the steps of the above-described method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system.

[0194] Embodiment 5 of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to any of the above embodiments is implemented.

[0195] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0196] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0197] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0198] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0199] If the integrated unit 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, in essence, 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. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0200] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing resonant overvoltage in an onshore wind power low-frequency AC system, characterized in that: include: In response to an overvoltage suppression request for an onshore wind power low-frequency AC system, a simulation model of the onshore wind power low-frequency AC system is constructed and associated electrical parameters are obtained; Using the electrical parameters to input a preset neutral point small reactance function, and outputting a plurality of initial neutral point small reactance values; Using a plurality of the initial neutral point small reactance values ​​to input the simulation model to perform overvoltage simulation of different types of typical faults, and generating overvoltage simulation results under each of the typical faults; Determine whether each overvoltage simulation result meets the preset standard overvoltage requirement; If the overvoltage simulation result meets the preset standard overvoltage requirement, the initial neutral point small reactance value associated with the overvoltage simulation result is used as the target neutral point small reactance value; The reactance parameter of the neutral point small reactance of the onshore wind power low-frequency AC system is adjusted according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

2. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 1, characterized in that: The electrical parameters include reactance values ​​of multiple parallel reactors, positive sequence capacitive reactance value of the overhead line and zero sequence capacitive reactance value of the overhead line.

3. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 2, characterized in that: The method of using the electrical parameters to input a preset neutral point small reactance function and outputting a plurality of initial neutral point small reactance values ​​comprises: Performing a difference operation using a positive-sequence capacitive reactance value of the overhead line and a zero-sequence capacitive reactance value of the overhead line to obtain a first difference; The reactance values ​​of the plurality of parallel reactors are respectively used with a preset small reactance coefficient to obtain a plurality of first multiplication values; Using a plurality of the first multiplication values ​​to perform difference operations with the preset small reactance coefficient respectively, to obtain a plurality of second difference values; Performing ratio operations on the first difference and the plurality of second difference values ​​to obtain a plurality of first ratios; A plurality of the first ratios are respectively used to perform ratio operations with the square values ​​of the reactance values ​​of the associated shunt reactors to obtain a plurality of initial neutral point small reactance values.

4. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 1, characterized in that: The typical fault is any one of a single-phase breaking fault, a two-phase breaking fault, a single-phase grounding fault and a two-phase grounding fault.

5. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 1, characterized in that: The overvoltage simulation results include line resonance overvoltage value, latent supply current and recovery voltage value.

6. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 5, characterized in that: The preset standard overvoltage requirements are that the line resonance overvoltage value is in a preset standard resonance overvoltage interval, the latent supply current is in a preset standard latent supply current interval, and the recovery voltage value is in a preset recovery voltage interval.

7. The method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to claim 1, characterized in that: The reactance parameter is the capacity of the parallel capacitor.

8. A resonant overvoltage suppression system for an onshore wind power low-frequency AC system, characterized in that: include: A response module, used to respond to an overvoltage suppression request for an onshore wind power low-frequency AC system, build a simulation model of the onshore wind power low-frequency AC system and obtain associated electrical parameters; An initial neutral point small reactance value module is used to use the electrical parameters to input a preset neutral point small reactance function and output a plurality of initial neutral point small reactance values; An overvoltage simulation module, used to use a plurality of the initial neutral point small reactance values ​​to input the simulation model to perform overvoltage simulation of different types of typical faults, and generate overvoltage simulation results under each of the typical faults; A judgment module is used to judge whether each overvoltage simulation result meets the preset standard overvoltage requirement; A target neutral point small reactance value module is used to use the initial neutral point small reactance value associated with the overvoltage simulation result as the target neutral point small reactance value if the overvoltage simulation result meets the preset standard overvoltage requirement; The adjustment module is used to adjust the reactance parameters of the neutral point small reactance of the onshore wind power low-frequency AC system according to the target neutral point small reactance value until the overvoltage value of the overhead line in the onshore wind power low-frequency AC system is within a preset standard overvoltage range.

9. An electronic device, characterized in that: It comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the method for suppressing resonant overvoltage of an onshore wind power low-frequency AC system according to any one of claims 1 to 7 is implemented.

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