Simulation of grid-connected stability of high penetration wind farm and method for optimizing control parameters

Abstract

This invention discloses a method for simulating grid-connected stability and optimizing control parameters of high-penetration wind farms, relating to the field of wind power generation technology. The method includes the following steps: A wind turbine model is created based on historical meteorological and wind data to obtain the historical power generation and rotational speed of the wind turbines, and a set of wind turbines based on wind speed levels is established; based on wind turbines with identified abnormal types and grid-side power demand, pitch angle control signals and charge / discharge control signals are generated; the wind turbine model conducts fault type tests based on a grid-connected fault type library and generates power recovery control signals to gradually restore wind turbine power; the power recovery rate coefficient is determined based on grid connection point voltage, short-circuit capacity, and short-circuit current, and the wind turbine power recovery rate is controlled based on phase-locked loop frequency deviation; this method improves the safe operation stability of the grid after high-penetration wind power is connected by controlling the wind turbine power recovery rate.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a method for simulating grid-connected stability and optimizing control parameters of high-penetration wind farms. Background Technology

[0002] With the continuous expansion of wind power development and its increasing penetration rate in the power system, the randomness and volatility of wind turbine output after a high proportion of wind power is connected to the grid can significantly impact the voltage and frequency stability of the power grid. Furthermore, wind power output fluctuations can easily trigger power oscillations in the power grid. Traditional grid connection control methods often employ fixed-parameter control strategies, which cannot dynamically adjust control actions based on abnormal wind turbine operation states within the wind farm or the real-time operational needs of the power grid. They also struggle to optimize the power recovery rate to match the actual carrying capacity of the power grid after fault clearing, easily leading to secondary oscillations during fault recovery and potentially causing large-scale grid disconnections and other safety incidents, seriously threatening the stable operation of the entire power system. Moreover, most existing optimization methods do not incorporate wind turbine operation anomaly classifications with actual power grid demand for parameter optimization. The optimization objectives have a low degree of matching with actual operational needs, making it difficult to effectively improve the stability of wind farm grid connection in high-penetration scenarios. Therefore, a more adaptable wind farm grid connection stability simulation optimization scheme is urgently needed to address the stability issues associated with high-penetration wind power grid connection. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a method for simulating grid-connected stability and optimizing control parameters of high-penetration wind farms. This method improves grid-connected stability by generating control signals based on the selection of wind turbines with abnormal types and the power demand of the grid side. Furthermore, it controls the power recovery rate of wind turbine generators by controlling the power recovery rate of wind turbine generators through the corrected corresponding wind turbine generator power recovery coefficient, thereby further improving the safe operation stability of the grid after high-penetration wind power is connected to the grid.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] The first aspect of this application provides a method for simulating grid-connected stability and optimizing control parameters of high-penetration wind farms, including the following steps: S101. The wind turbine model is based on historical meteorological and wind power data to obtain the historical power generation and speed of the wind turbine, and establishes a set of wind turbines based on wind speed levels. S102. Filter the set of wind turbine units of wind speed level to find wind turbines with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and mark the abnormality type. S103. Based on the wind turbines with abnormal types that have been screened out and the power demand on the grid side, generate pitch angle control signals and charge / discharge control signals to improve grid connection stability; S104. The wind turbine model conducts fault type tests based on the grid connection fault type library and generates power recovery control signals to gradually restore the power of the wind turbine. S105. Determine the power recovery rate coefficient based on the grid connection point voltage, short-circuit capacity, and short-circuit current, and control the power recovery rate of the wind turbine generator based on the phase-locked loop frequency deviation.

[0006] Furthermore, the wind turbine model, based on historical meteorological and wind power data, obtains the historical power generation and historical rotational speed of the wind turbine, and establishes a set of wind turbines according to wind speed levels, including the following steps: Historical meteorological data is used as input data for the basic model of wind turbines to obtain the historical power generation and historical rotational speed of wind turbines. Historical meteorological wind data is classified into wind speed levels based on wind speed magnitude. These wind speed levels include weak wind level, strong wind level, gale wind level, and super strong wind level. Based on wind speed levels, the historical power generation and speed of wind turbines are classified and stored, and a set of historical power generation and speed of wind turbines corresponding to different wind speed levels is established to obtain a set of wind turbines by wind speed level.

[0007] Furthermore, the set of wind turbine units at different wind speed levels is screened to identify those with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and the abnormality type is marked, including the following steps: Calculate the average historical power generation of wind turbines under the same wind speed level. Subtract the historical power generation of a single wind turbine from the average to obtain the historical power generation difference value. If the absolute value of the historical power generation difference value is less than the power generation abnormality threshold, the power generation of the turbine is determined to be normal. If the absolute value of the historical power generation difference value is greater than or equal to the power generation abnormality threshold, the power generation of the turbine is determined to be abnormal, and the turbine is marked as having a power generation abnormality type, which includes power generation abnormality type and power generation abnormality type. Calculate the average historical speed of wind turbine units under the same wind speed level, and subtract the historical speed of a single wind turbine from the average speed to obtain the historical speed difference value. If the absolute value of the historical speed difference value is less than the speed abnormality threshold, the speed of the motor is determined to be normal. If the absolute value of the historical speed difference value is greater than or equal to the speed abnormality threshold, the speed of the motor is determined to be abnormal, and the motor is marked as a speed abnormality type.

[0008] Furthermore, based on the screened wind turbines exhibiting abnormal types and the grid-side power demand, pitch angle control signals and charge / discharge control signals are generated to improve grid connection stability, including the following steps: Calculate the total power generation of the generator set at the current historical moment and compare it with the power demand issued by the grid. If the total power generation of the wind turbine cannot meet the power demand of the grid, a pitch angle reduction control signal and / or a discharge control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is not fully charged, a charging control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is saturated, then the pitch angle increase control signal or grid disconnection control signal will be generated first based on the turbine with abnormal power generation.

[0009] Furthermore, if the total power generation of the wind turbine cannot meet the electricity demand of the grid, the generation of the pitch angle reduction control signal and / or discharge control signal includes the following steps: If there are wind turbines with abnormally low power generation, a control signal to reduce the pitch angle is generated based on the wind turbine with abnormally low power generation to increase the wind-receiving area of ​​the wind turbine blades and thus increase the power generation of the wind turbine. If the total power generation of the wind turbine still does not meet the power demand of the grid after the pitch angle reduction adjustment, a discharge control signal is generated to control the battery energy storage unit to discharge in order to ensure that the total output power matches the power demand of the grid. If there are no wind turbines with abnormally low power generation, a discharge control signal is generated.

[0010] Furthermore, if the total power generation of the wind turbine can meet the grid's electricity demand and the energy storage battery is saturated, then the generation of a pitch angle increase control signal or grid disconnection control signal is prioritized for turbines with abnormal power generation, including the following steps: If there are wind turbines with abnormally high power generation, a control signal to increase the pitch angle is generated based on the wind turbines with abnormally high power generation to control the wind turbines with abnormally high power generation to reduce their power generation. If there are wind turbines with abnormally low power generation, a grid disconnection control signal is generated based on the wind turbines with abnormally low power generation to control the wind turbines with abnormally low power generation to disconnect from the grid. If there are no wind turbines with abnormal power generation, a grid disconnection control signal is generated based on the difference between the total power generation of the wind turbine and the power demand on the grid side to control the corresponding wind turbine to disconnect from the grid.

[0011] Furthermore, the wind turbine model conducts fault type tests based on a fault type library and generates power recovery control signals to gradually restore the wind turbine power, including the following steps: Import the various grid connection fault types from the grid connection fault type library into the wind turbine model in sequence, and trigger the corresponding fault scenario. Record the voltage fluctuation amplitude, active power oscillation range, and wind turbine speed change data at the grid connection point after the fault occurs, and perform fault clearing operations according to the preset timing sequence. After the fault is cleared, the system detects the deviation between the current grid connection point voltage and active power, and generates a phased power recovery control signal based on the wind turbine's operating status and the remaining power of the battery storage unit to gradually restore the wind turbine's power generation.

[0012] Furthermore, after the fault is cleared, the deviation between the current grid connection point voltage and active power of the detection system is used, and a phased power recovery control signal is generated based on the wind turbine operating status and the remaining power of the battery energy storage unit to gradually restore the wind turbine's generating power, including the following steps: S41. First, check whether the grid connection point voltage is less than the stable operating voltage threshold. If the grid connection point voltage is less than the stable operating voltage threshold, generate a discharge control signal to control the battery energy storage unit to increase the discharge power. After the grid connection point voltage is increased to the stable operating voltage range, execute step S42. If the grid connection point voltage is greater than or equal to the stable operating voltage threshold, execute step S42. S42. Generate a phased power recovery control signal according to the power recovery method of prioritizing wind turbines without abnormal type markings and delaying wind turbines with abnormal type markings, so as to restore the power generation of wind turbine units in batches until all wind turbines are connected to the grid and then execute step S43 to avoid secondary oscillation of the system caused by a one-time power recovery. S43. Detect the deviation between the current total power generation of the wind turbine and the power demand on the grid side. If the total power generation of the wind turbine does not match the power demand on the grid side, generate a pitch angle control signal and a charge / discharge control signal to fine-tune the output power. If the total power generation of the wind turbine matches the power demand on the grid side, no power fine-tuning is required.

[0013] Furthermore, determining the power recovery rate coefficient based on grid connection point voltage, short-circuit capacity, and short-circuit current, and controlling the power recovery rate of the wind turbine generator based on the phase-locked loop frequency deviation includes the following steps: The grid short-circuit ratio is determined based on the grid connection point voltage, short-circuit capacity, and short-circuit current, and the corresponding wind turbine power recovery coefficient is mapped according to the grid short-circuit ratio. The power recovery coefficient of the wind turbine is corrected based on the frequency deviation of the phase-locked loop, and the corrected power recovery coefficient of the corresponding wind turbine is obtained. The power recovery rate of the wind turbine is controlled based on the corrected corresponding wind turbine power recovery coefficient, and its expression is as follows: ; in, This represents the restored power output of the generator set. This represents the generator set's power output before the fault. The lowest power output of the generator set with the faulty component. This represents the corrected power recovery coefficient for the corresponding wind turbine unit. The baseline recovery time.

[0014] Furthermore, the power recovery coefficient of the wind turbine is corrected based on the phase-locked loop frequency deviation to obtain the corrected power recovery coefficient of the corresponding wind turbine; this includes the following steps: If the second frequency deviation setting threshold is greater than the first frequency deviation setting threshold, and the phase-locked loop frequency deviation is less than or equal to the first frequency deviation setting threshold, then the correction coefficient is set to 1 and multiplied by the wind turbine power recovery coefficient to obtain the corrected corresponding wind turbine power recovery coefficient. If the phase-locked loop frequency deviation is greater than the first frequency deviation setting threshold and less than the second frequency deviation setting threshold, then the correction coefficient is set to 0.5 and multiplied by the wind turbine power recovery coefficient to obtain the corrected corresponding wind turbine power recovery coefficient. If the phase-locked loop frequency deviation is greater than or equal to the second frequency deviation setting threshold, the correction coefficient is set to 0 and multiplied by the wind turbine power recovery coefficient to obtain the corrected wind turbine power recovery coefficient.

[0015] The beneficial effects of this application are as follows: It enables the classification and labeling of wind turbine abnormal operating states, and dynamically adjusts the pitch angle control and energy storage charging / discharging strategies in conjunction with real-time grid demand. This ensures that output power matches power demand while screening abnormal wind turbines, preventing the continuous impact of abnormal operating states on grid stability. After fault clearance, a phased power recovery strategy is adopted, prioritizing the recovery of turbines without abnormalities and gradually increasing power generation, effectively avoiding secondary oscillations caused by a one-time power recovery. Simultaneously, the power recovery coefficient of the wind turbines is dynamically corrected by combining the actual short-circuit capacity of the grid with the real-time frequency deviation of the phase-locked loop, and the power recovery rate is adjusted to match the actual grid carrying capacity, further reducing the risk of frequency instability and secondary oscillations during fault recovery. This effectively solves the problems of poor adaptability and low matching degree between optimization objectives and actual operating requirements of traditional fixed-parameter control strategies, significantly improving the stability of wind farm grid-connected operation in high-penetration scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram illustrating the steps of the high-penetration wind farm grid connection stability simulation and control parameter optimization method of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1 A method for simulating grid-connected stability and optimizing control parameters in high-penetration wind farms includes the following steps: S101. The wind turbine model is based on historical meteorological and wind power data to obtain the historical power generation and speed of the wind turbine, and establishes a set of wind turbines based on wind speed levels. Acquire wind turbine data, battery storage component data, and historical meteorological and wind speed data (optionally, data from the past 3 years). Construct a wind turbine model based on the wind turbine and battery storage component data. Use the historical meteorological and wind speed data as input to the wind turbine model to obtain historical power generation and historical rotational speed of the wind turbine. Classify the historical meteorological and wind speed data according to wind speed: 0-11 km / h is classified as weak wind, 12-49 km / h as strong wind, 50-88 km / h as very strong wind, and above 89 km / h as extremely strong wind. Since wind speeds above 89 km / h can damage wind turbines and require shutdown, data at the extremely strong wind level are removed from the historical meteorological and wind speed data. The wind speed is classified as weak wind.

[0021] The wind turbine model is based on historical meteorological wind data to obtain the historical power generation and rotational speed of the wind turbines. It then establishes a set of wind turbines based on wind speed levels, including the following steps: Historical meteorological data is used as input data for the basic model of wind turbines to obtain the historical power generation and historical rotational speed of wind turbines. Historical meteorological wind data is classified into wind speed levels based on wind speed magnitude. These wind speed levels include weak wind level, strong wind level, gale wind level, and super strong wind level. Based on wind speed levels, the historical power generation and speed of wind turbines are classified and stored, and a set of historical power generation and speed of wind turbines corresponding to different wind speed levels is established to obtain a set of wind turbines by wind speed level.

[0022] S102. Filter the set of wind turbine units of wind speed level to find wind turbines with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and mark the abnormality type. The wind turbine set by wind speed level includes sets of wind turbines for weak winds, strong winds, high winds, and very strong winds. Because the power generation of wind turbines is negligible under weak wind conditions, and requires emergency shutdown to avoid damage under very strong wind conditions (i.e., power generation is zero), anomaly thresholds for power generation and rotational speed are set. Based on these thresholds, wind turbines with historical power generation anomalies and / or historical rotational speed anomalies under the same wind speed level are selected from the sets of wind turbines at different wind speed levels. Optionally, the historical average power generation under the same wind speed level is calculated, and the difference is calculated between this average and the historical power generation. If the absolute value of the historical power generation difference is less than the power generation anomaly threshold, the power generation of the motor is considered normal; if the absolute value is greater than or equal to the power generation anomaly threshold, the power generation of the motor is considered abnormal, and the motor is marked as having an abnormal power generation type. Similarly, the historical average rotational speed under the same wind speed level is calculated, and the difference is calculated between this average and the historical rotational speed. If the absolute value of the historical rotational speed difference is less than the rotational speed anomaly threshold, the rotational speed of the motor is considered normal; if the absolute value is greater than or equal to the rotational speed anomaly threshold, the rotational speed of the motor is considered abnormal, and the motor is marked as having an abnormal rotational speed type.

[0023] The process of filtering wind turbine sets by wind speed level to identify those with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and then marking the abnormality type, includes the following steps: Calculate the average historical power generation of wind turbines under the same wind speed level. Subtract the historical power generation of a single wind turbine from the average to obtain the historical power generation difference value. If the absolute value of the historical power generation difference value is less than the power generation abnormality threshold, the power generation of the turbine is determined to be normal. If the absolute value of the historical power generation difference value is greater than or equal to the power generation abnormality threshold, the power generation of the turbine is determined to be abnormal, and the turbine is marked as having a power generation abnormality type, which includes power generation abnormality type and power generation abnormality type. Calculate the average historical speed of wind turbine units under the same wind speed level, and subtract the historical speed of a single wind turbine from the average speed to obtain the historical speed difference value. If the absolute value of the historical speed difference value is less than the speed abnormality threshold, the speed of the motor is determined to be normal. If the absolute value of the historical speed difference value is greater than or equal to the speed abnormality threshold, the speed of the motor is determined to be abnormal, and the motor is marked as a speed abnormality type.

[0024] S103. Based on the wind turbines with abnormal types that have been screened out and the power demand on the grid side, generate pitch angle control signals and charge / discharge control signals to improve grid connection stability; Wind turbines exhibiting abnormal characteristics are identified, including those with abnormal rotational speed and abnormal power generation. If the total power generation of the wind turbine cannot meet the grid's electricity demand, a pitch angle control signal and / or a discharge control signal are generated to increase the total output power of the wind turbine system to meet the grid's electricity demand. The pitch angle control signal includes a pitch angle reduction control signal and a pitch angle increase control signal. The pitch angle reduction control signal increases the wind-receiving area of ​​the turbine blades to increase the turbine's power generation, while the pitch angle increase control signal decreases the wind-receiving area of ​​the turbine blades to reduce the turbine's power generation. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is not fully charged, a charging control signal is generated to charge the energy storage battery. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is fully charged, a pitch angle control signal is generated first, based on the motors with abnormal power generation, to control the motors with excessively high power generation to reduce their power generation, and a grid disconnection control signal is generated to control the motors with excessively low power generation to disconnect from the grid, so as to avoid large fluctuations in output power affecting grid connection stability.

[0025] Based on the screened wind turbines exhibiting abnormal types and the grid-side power demand, pitch angle control signals and charge / discharge control signals are generated to improve grid connection stability, including the following steps: Calculate the total power generation of the generator set at the current historical moment and compare it with the power demand issued by the grid. If the total power generation of the wind turbine cannot meet the power demand of the grid, a pitch angle reduction control signal and / or a discharge control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is not fully charged, a charging control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is saturated, then the pitch angle increase control signal or grid disconnection control signal will be generated first based on the turbine with abnormal power generation.

[0026] If the total power generation of the wind turbine cannot meet the electricity demand of the grid, the generation of the pitch angle reduction control signal and / or discharge control signal includes the following steps: If there are wind turbines with abnormally low power generation, a control signal to reduce the pitch angle is generated based on the wind turbine with abnormally low power generation to increase the wind-receiving area of ​​the wind turbine blades and thus increase the power generation of the wind turbine. If the total power generation of the wind turbine still does not meet the power demand of the grid after the pitch angle reduction adjustment, a discharge control signal is generated to control the battery energy storage unit to discharge in order to ensure that the total output power matches the power demand of the grid. If there are no wind turbines with abnormally low power generation, a discharge control signal is generated.

[0027] If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is saturated, then the generation of a pitch angle increase control signal or grid disconnection control signal is prioritized for turbines with abnormal power generation, including the following steps: If there are wind turbines with abnormally high power generation, a control signal to increase the pitch angle is generated based on the wind turbines with abnormally high power generation to control the wind turbines with abnormally high power generation to reduce their power generation. If there are wind turbines with abnormally low power generation, a grid disconnection control signal is generated based on the wind turbines with abnormally low power generation to control the wind turbines with abnormally low power generation to disconnect from the grid. If there are no wind turbines with abnormal power generation, a grid disconnection control signal is generated based on the difference between the total power generation of the wind turbine and the power demand on the grid side to control the corresponding wind turbine to disconnect from the grid.

[0028] S104. The wind turbine model conducts fault type tests based on the grid connection fault type library and generates power recovery control signals to gradually restore the power of the wind turbine. The wind turbine model is tested for various fault types based on a grid-connected fault type library, which includes three-phase short-circuit faults, single-phase grounding faults, line disconnection faults, and voltage drop faults. Different grid-connected fault scenarios are sequentially loaded into the constructed wind turbine model. The voltage fluctuations, power oscillations at the wind turbine's grid connection point, and the wind turbine's own speed changes are recorded after a fault occurs. When a fault is triggered, the faulty line is disconnected according to a preset fault clearing logic to terminate the fault's continued impact on the entire system. Based on the system stability requirements under the current fault scenario, and considering the current wind turbine operating status (wind turbine operating status refers to turbines with and without anomaly type markers) and the remaining charge of the energy storage battery, a phased power recovery control signal is generated. First, the energy storage discharge power is gradually increased to support the system voltage. Then, according to the priority of the anomaly markers, the power generation output of the normal wind turbines is gradually restored to avoid secondary oscillations caused by excessively rapid power recovery.

[0029] The wind turbine model conducts fault type tests based on a fault type library and generates power recovery control signals to gradually restore the wind turbine power, including the following steps: Import the various grid connection fault types from the grid connection fault type library into the wind turbine model in sequence, and trigger the corresponding fault scenario. Record the voltage fluctuation amplitude, active power oscillation range, and wind turbine speed change data at the grid connection point after the fault occurs, and perform fault clearing operations according to the preset timing sequence. After the fault is cleared, the system detects the deviation between the current grid connection point voltage and active power, and generates a phased power recovery control signal based on the wind turbine's operating status and the remaining power of the battery storage unit to gradually restore the wind turbine's power generation.

[0030] After the fault is cleared, the deviation between the current grid connection point voltage and active power of the detection system is used. Based on the operating status of the wind turbine and the remaining power of the battery storage unit, a phased power recovery control signal is generated to gradually restore the wind turbine's generating power. This includes the following steps: S41. First, check whether the grid connection point voltage is less than the stable operating voltage threshold. If the grid connection point voltage is less than the stable operating voltage threshold, generate a discharge control signal to control the battery energy storage unit to increase the discharge power. After the grid connection point voltage is increased to the stable operating voltage range, execute step S42. If the grid connection point voltage is greater than or equal to the stable operating voltage threshold, execute step S42. S42. Generate a phased power recovery control signal according to the power recovery method of prioritizing wind turbines without abnormal type markings and delaying wind turbines with abnormal type markings, so as to restore the power generation of wind turbine units in batches until all wind turbines are connected to the grid and then execute step S43 to avoid secondary oscillation of the system caused by a one-time power recovery. S43. Detect the deviation between the current total power generation of the wind turbine and the power demand on the grid side. If the total power generation of the wind turbine does not match the power demand on the grid side, generate a pitch angle control signal and a charge / discharge control signal to fine-tune the output power. If the total power generation of the wind turbine matches the power demand on the grid side, no power fine-tuning is required.

[0031] S105. Determine the power recovery rate coefficient based on the grid connection point voltage, short-circuit capacity and short-circuit current, and control the power recovery rate of the wind turbine generator based on the phase-locked loop frequency deviation. The grid short-circuit ratio is determined by acquiring the grid connection point voltage, short-circuit capacity, and short-circuit current. Optionally, grid strength levels can be set, including extremely weak, weak, moderate, and strong grid strength levels. Grid strength levels can be classified based on the grid short-circuit ratio. For example, a short-circuit ratio less than or equal to 1.5 is classified as extremely weak; a short-circuit ratio greater than 1.5 and less than or equal to 3 is classified as weak; a short-circuit ratio greater than 3 and less than or equal to 5 is classified as moderate; and a short-circuit ratio greater than 5 is classified as strong. The power recovery coefficient of wind turbines can be mapped to the grid short-circuit ratio. For example, the power recovery coefficient for wind turbines is 0.2 for extremely weak grid strength, 0.4 for weak grid strength, 0.7 for medium grid strength, and 1 for strong grid strength. It should be noted that the difference between the instantaneous angular frequency of the voltage-controlled oscillator (VCO) at the PLL output and the angular frequency of the reference signal is calculated to obtain the PLL frequency deviation. The power recovery coefficient of the wind turbines is corrected based on this PLL frequency deviation, and the corrected coefficient is used to control the power recovery rate of the wind turbines, further improving the stability of the wind turbine power recovery.

[0032] Determining the power recovery rate coefficient based on grid connection point voltage, short-circuit capacity, and short-circuit current, and controlling the power recovery rate of wind turbine generators based on phase-locked loop frequency deviation, includes the following steps: The grid short-circuit ratio is determined based on the grid connection point voltage, short-circuit capacity, and short-circuit current, and the corresponding wind turbine power recovery coefficient is mapped according to the grid short-circuit ratio. The power recovery coefficient of the wind turbine is corrected based on the phase-locked loop (PLL) frequency deviation to obtain the corrected power recovery coefficient. Optionally, if the second frequency deviation threshold is greater than the first frequency deviation threshold, and the PLL frequency deviation is less than or equal to the first frequency deviation threshold, the correction coefficient is set to 1 and multiplied by the wind turbine power recovery coefficient to obtain the corrected power recovery coefficient. If the PLL frequency deviation is greater than the first frequency deviation threshold and less than the second frequency deviation threshold, the correction coefficient is set to 0.5 and multiplied by the wind turbine power recovery coefficient to obtain the corrected power recovery coefficient. If the PLL frequency deviation is greater than or equal to the second frequency deviation threshold, the correction coefficient is set to 0 and multiplied by the wind turbine power recovery coefficient to obtain the corrected power recovery coefficient (for wind turbine power generation recovery after suspension). The power recovery rate of the wind turbine is controlled based on the corrected corresponding wind turbine power recovery coefficient, and its expression is as follows: ; in, This represents the restored power output of the generator set. This represents the generator set's power output before the fault. The lowest power output of the generator set with the faulty component. This represents the corrected power recovery coefficient for the corresponding wind turbine unit. The baseline recovery time.

[0033] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0034] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for simulating grid-connected stability and optimizing control parameters of high-penetration wind farms, characterized in that, Includes the following steps: S101. The wind turbine model is based on historical meteorological and wind power data to obtain the historical power generation and speed of the wind turbine, and establishes a set of wind turbines based on wind speed levels. S102. Filter the set of wind turbine units of wind speed level to find wind turbines with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and mark the abnormality type. S103. Based on the wind turbines with abnormal types that have been screened out and the power demand on the grid side, generate pitch angle control signals and charge / discharge control signals to improve grid connection stability; S104. The wind turbine model conducts fault type tests based on the grid connection fault type library and generates power recovery control signals to gradually restore the power of the wind turbine. S105. Determine the power recovery rate coefficient based on the grid connection point voltage, short-circuit capacity, and short-circuit current, and control the power recovery rate of the wind turbine generator based on the phase-locked loop frequency deviation.

2. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 1, characterized in that, The wind turbine model is based on historical meteorological wind data to obtain the historical power generation and rotational speed of the wind turbine. The process of establishing a set of wind turbines based on wind speed levels includes the following steps: Historical meteorological data is used as input data for the basic model of wind turbines to obtain the historical power generation and historical rotational speed of wind turbines. Historical meteorological wind data is classified into wind speed levels based on wind speed magnitude. These wind speed levels include weak wind level, strong wind level, gale wind level, and super strong wind level. Based on wind speed levels, the historical power generation and speed of wind turbines are classified and stored, and a set of historical power generation and speed of wind turbines corresponding to different wind speed levels is established to obtain a set of wind turbines by wind speed level.

3. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 1, characterized in that, The process of filtering the set of wind turbines by wind speed level to identify those with abnormal historical power generation and / or abnormal historical speed under the same wind speed level, and then marking the abnormality type, includes the following steps: Calculate the average historical power generation of wind turbines under the same wind speed level. Subtract the historical power generation of a single wind turbine from the average to obtain the historical power generation difference value. If the absolute value of the historical power generation difference value is less than the power generation abnormality threshold, the power generation of the turbine is determined to be normal. If the absolute value of the historical power generation difference value is greater than or equal to the power generation abnormality threshold, the power generation of the turbine is determined to be abnormal, and the turbine is marked as having a power generation abnormality type, which includes power generation abnormality type and power generation abnormality type. Calculate the average historical speed of wind turbine units under the same wind speed level, and subtract the historical speed of a single wind turbine from the average speed to obtain the historical speed difference value. If the absolute value of the historical speed difference value is less than the speed abnormality threshold, the speed of the motor is determined to be normal. If the absolute value of the historical speed difference value is greater than or equal to the speed abnormality threshold, the speed of the motor is determined to be abnormal, and the motor is marked as a speed abnormality type.

4. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 1, characterized in that, The process of generating pitch angle control signals and charge / discharge control signals based on wind turbines identified as having abnormal types and grid-side power demand to improve grid connection stability includes the following steps: Calculate the total power generation of the generator set at the current historical moment and compare it with the power demand issued by the grid. If the total power generation of the wind turbine cannot meet the power demand of the grid, a pitch angle reduction control signal and / or a discharge control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is not fully charged, a charging control signal will be generated. If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is saturated, then the pitch angle increase control signal or grid disconnection control signal will be generated first based on the turbine with abnormal power generation.

5. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 4, characterized in that, If the total power generation of the wind turbine cannot meet the power demand of the grid, the generation of the pitch angle reduction control signal and / or discharge control signal includes the following steps: If there are wind turbines with abnormally low power generation, a control signal to reduce the pitch angle is generated based on the wind turbine with abnormally low power generation to increase the wind-receiving area of ​​the wind turbine blades and thus increase the power generation of the wind turbine. If the total power generation of the wind turbine still does not meet the power demand of the grid after the pitch angle reduction adjustment, a discharge control signal is generated to control the battery energy storage unit to discharge in order to ensure that the total output power matches the power demand of the grid. If there are no wind turbines with abnormally low power generation, a discharge control signal is generated.

6. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 4, characterized in that, If the total power generation of the wind turbine can meet the power demand of the grid and the energy storage battery is saturated, then the generation of a pitch angle increase control signal or grid disconnection control signal based on the turbine with abnormal power generation includes the following steps: If there are wind turbines with abnormally high power generation, a control signal to increase the pitch angle is generated based on the wind turbines with abnormally high power generation to control the wind turbines with abnormally high power generation to reduce their power generation. If there are wind turbines with abnormally low power generation, a grid disconnection control signal is generated based on the wind turbines with abnormally low power generation to control the wind turbines with abnormally low power generation to disconnect from the grid. If there are no wind turbines with abnormal power generation, a grid disconnection control signal is generated based on the difference between the total power generation of the wind turbine and the power demand on the grid side to control the corresponding wind turbine to disconnect from the grid.

7. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 1, characterized in that, The wind turbine model performs fault type tests based on a fault type library and generates a power recovery control signal to gradually restore the wind turbine power, including the following steps: Import the various grid connection fault types from the grid connection fault type library into the wind turbine model in sequence, and trigger the corresponding fault scenario. Record the voltage fluctuation amplitude, active power oscillation range, and wind turbine speed change data at the grid connection point after the fault occurs, and execute the fault clearing operation according to the preset timing sequence. After the fault is cleared, the system detects the deviation between the current grid connection point voltage and active power, and generates a phased power recovery control signal based on the wind turbine's operating status and the remaining power of the battery storage unit to gradually restore the wind turbine's power generation.

8. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 7, characterized in that, After the fault is cleared, the deviation between the current grid connection point voltage and active power of the detection system is used, and a phased power recovery control signal is generated based on the wind turbine operating status and the remaining power of the battery energy storage unit to gradually restore the wind turbine's power generation capacity, including the following steps: S41. First, check whether the grid connection point voltage is less than the stable operating voltage threshold. If the grid connection point voltage is less than the stable operating voltage threshold, generate a discharge control signal to control the battery energy storage unit to increase the discharge power. After the grid connection point voltage is increased to the stable operating voltage range, execute step S42. If the grid connection point voltage is greater than or equal to the stable operating voltage threshold, execute step S42. S42. Generate a phased power recovery control signal according to the power recovery method of prioritizing wind turbines without abnormal type markings and delaying wind turbines with abnormal type markings, so as to restore the power generation of wind turbine units in batches until all wind turbines are connected to the grid and then execute step S43 to avoid secondary oscillation of the system caused by a one-time power recovery. S43. Detect the deviation between the current total power generation of the wind turbine and the power demand on the grid side. If the total power generation of the wind turbine does not match the power demand on the grid side, generate a pitch angle control signal and a charge / discharge control signal to fine-tune the output power. If the total power generation of the wind turbine matches the power demand on the grid side, no power fine-tuning is required.

9. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 1, characterized in that, The process of determining the power recovery rate coefficient based on grid connection point voltage, short-circuit capacity, and short-circuit current, and controlling the power recovery rate of the wind turbine generator based on the phase-locked loop frequency deviation, includes the following steps: The grid short-circuit ratio is determined based on the grid connection point voltage, short-circuit capacity, and short-circuit current, and the corresponding wind turbine power recovery coefficient is mapped according to the grid short-circuit ratio. The power recovery coefficient of the wind turbine is corrected based on the frequency deviation of the phase-locked loop, and the corrected power recovery coefficient of the corresponding wind turbine is obtained. The power recovery rate of the wind turbine is controlled based on the corrected corresponding wind turbine power recovery coefficient, and its expression is as follows: ； in, This represents the restored power output of the generator set. This represents the generator set's power output before the fault. The lowest power output of the generator set with the faulty component. This represents the corrected power recovery coefficient for the corresponding wind turbine unit. The baseline recovery time.

10. The method for simulating grid-connected stability and optimizing control parameters of a high-penetration wind farm according to claim 9, characterized in that, The power recovery coefficient of the wind turbine is corrected based on the phase-locked loop frequency deviation to obtain the corrected power recovery coefficient of the corresponding wind turbine. Includes the following steps: If the second frequency deviation setting threshold is greater than the first frequency deviation setting threshold, and the phase-locked loop frequency deviation is less than or equal to the first frequency deviation setting threshold, then the correction coefficient is set to 1 and multiplied by the wind turbine power recovery coefficient to obtain the corrected corresponding wind turbine power recovery coefficient. If the phase-locked loop frequency deviation is greater than the first frequency deviation setting threshold and less than the second frequency deviation setting threshold, then the correction coefficient is set to 0.5 and multiplied by the wind turbine power recovery coefficient to obtain the corrected corresponding wind turbine power recovery coefficient. If the phase-locked loop frequency deviation is greater than or equal to the second frequency deviation setting threshold, the correction coefficient is set to 0 and multiplied by the wind turbine power recovery coefficient to obtain the corrected wind turbine power recovery coefficient.

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