Wind power plant unit-station cooperative frequency modulation control method

Abstract

The invention belongs to the technical field of new energy power generation system frequency modulation, and particularly relates to a wind power plant unit-station cooperative frequency modulation control method. Comprising the following steps: establishing a wind power plant cooperative adaptive frequency modulation control architecture based on overspeed control priority; based on the control architecture, considering adaptive control of frequency modulation parameters, and determining that virtual inertia control and droop control are respectively configured in a unit-level frequency modulation controller and a station-level frequency modulation controller; preferential load shedding and frequency modulation are controlled based on virtual inertia and droop overspeed, and a variable pitch unit is used for supplementing power vacancy; and according to a frequency modulation parameter adaptive control result, variable pitch control supplementation load shedding and frequency modulation power vacancy, adaptive adjustment is performed on a frequency modulation coefficient, and wind power plant unit-station cooperative frequency modulation control is completed in combination with supplementation power vacancy. According to the method, mechanical wear caused by frequent action of the variable-pitch unit is reduced, the frequency modulation performance of each unit is fully exerted, and the frequency modulation performance and reliability of the wind power plant are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of frequency regulation of renewable energy power generation systems, and in particular relates to a wind farm unit-station coordinated frequency regulation control method, and more specifically to a wind farm unit-station coordinated frequency regulation control method based on overspeed control priority. Background Art

[0002] As the penetration rate of wind power in my country gradually increases, the inertia and frequency regulation capabilities of the power system continue to decline, and there is an urgent need for wind farms to participate in system frequency regulation.

[0003] Currently, there are many solutions for coordinated frequency control of wind farms, such as:

[0004] A wind farm active power allocation method based on turbine classification is studied. Based on the predicted wind speed, current wind speed, and output power of each turbine, this article uses a fuzzy C-means classification method to propose a wind farm active power allocation method that can accurately track the wind farm's active output power. However, this method suffers from complex communication and algorithms, making it difficult to implement collaborative mechanisms in practice.

[0005] This paper proposes an adaptive frequency control strategy for wind farms that considers optimal rotor kinetic energy. This strategy uses a variable droop gain to maximize the utilization of rotor kinetic energy in grid frequency regulation under load shedding conditions. However, this approach does not consider turbines with pitch-angle load shedding and therefore cannot cover medium- and high-speed wind speeds.

[0006] While the aforementioned existing station-level control methods have proposed various wind farm active power distribution and adaptive frequency control strategies that can accurately track wind farm active output, and research has also explored maximizing the utilization of rotor kinetic energy in wind farms under load reduction to participate in grid frequency regulation, these traditional station-level frequency regulation control methods, however, suffer from high communication and algorithm complexity, making collaborative mechanisms difficult to implement in practice. Furthermore, they lack effective utilization of the frequency regulation capabilities of pitch-angle-based load reduction units in medium and high wind speed scenarios, limiting the station's frequency regulation response performance. There is an urgent need to fully leverage the frequency regulation performance of each unit within the station based on its operating status and control methods.

[0007] As one of the main power sources for future power systems, developing a reasonable and effective method for coordinated frequency regulation in wind farms is one of the keys to solving the current system frequency problem. Therefore, it is necessary to propose a wind farm unit-station coordinated frequency regulation method that can reduce pitch unit motion and simultaneously consider adaptive adjustment of the virtual inertia control coefficient and droop control coefficient. Summary of the Invention

[0008] To address the shortcomings of the aforementioned prior art, the present invention provides a method for coordinated frequency regulation control of wind farm units and stations based on overspeed control priority. This method aims to achieve coordinated frequency regulation control of wind farm units and stations by prioritizing overspeed control for load shedding and standby, prioritizing frequency regulation response for overspeeding units, and adaptively adjusting the frequency regulation control coefficient. This method reduces mechanical wear caused by the frequent operation of variable-pitch units, maximizes the frequency regulation performance of each unit, and improves the frequency regulation capability of the wind farm, thereby achieving the invention's purpose of coordinated frequency regulation control of wind farm units and stations.

[0009] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0010] The wind farm unit-station coordinated frequency regulation control method includes the following steps:

[0011] Establish a wind farm collaborative adaptive frequency control architecture based on overspeed control priority;

[0012] Based on the control architecture and considering the adaptive control of frequency regulation parameters, it is determined that virtual inertia control and droop control are configured in the unit-level frequency regulation controller and the station-level frequency regulation controller respectively;

[0013] Prioritize load shedding and frequency regulation based on virtual inertia and droop overspeed control, and use variable pitch units to supplement power shortages;

[0014] According to the adaptive control results of the frequency regulation parameters, pitch control supplements the load shedding and frequency regulation power shortage, completing the wind farm unit-station coordinated frequency regulation control.

[0015] Furthermore, the load reduction is achieved by calculating the field control load reduction instruction and judging the working range of each unit. Based on the principle of overspeed control priority, the rotor kinetic energy is used to evaluate and distribute the active reserve of each overspeed unit. If it is insufficient, the variable pitch control is used to evenly distribute the active reserve to achieve the station load reduction target. The steps include:

[0016] A1. The wind farm central controller calculates the wind farm load shedding power reserve command value based on the site size and load shedding reserve requirements;

[0017] A2. Use the wind farm's load shedding power reserve command value and the operating status of each unit to allocate the load shedding power;

[0018] A3. Calculate the maximum active reserve ΔP provided by all overspeed units del_sum ;

[0019] A4. Compare the wind farm load shedding power reserve command value ΔP delN and the maximum active reserve ΔP in step A3 del_sum The size of ΔP del_sum <ΔP delN, then go to step A7, otherwise evaluate the load shedding capacity of each overspeed unit;

[0020] A5. If P del_sum ≥ΔP delN , then only the overspeed units can meet the station load reduction requirements, and the load reduction capacity of each overspeed unit is evaluated using the rotor kinetic energy;

[0021] A6. When P del_sum ≥ΔP delN When the load shedding capacity evaluation coefficient of the overspeed unit is used, the load shedding power ΔP of the wind farm is calculated. delN Make an allocation;

[0022] A7. When ΔP del_sum <ΔP delN When the overspeed unit is loaded down according to the maximum active reserve, the remaining required load shedding active power is calculated;

[0023] A8. Using the average distribution method, for the remaining required load shedding active power ΔP del_r , calculate the standby active power of the j-th variable pitch unit.

[0024] Furthermore, the maximum active reserve capacity ΔP that can be provided by all the overspeed units is del_sum , as shown below:

[0025]

[0026] Where: ΔP del_maxi is the maximum load-shedding active power of the i-th unit in the wind farm operating in the MPPT zone.

[0027] Furthermore, the load shedding capacity evaluation coefficient calculation result is a i , the load shedding capacity assessment coefficient a of the i-th overspeed unit i The maximum rotor kinetic energy that can be released by the i-th unit is calculated as shown in equations (2) and (3):

[0028]

[0029] Where: ΔE k_max i is the maximum rotor kinetic energy that can be released by the i-th unit, J is the moment of inertia of the fan, ω N is the rated speed of the unit, ω opti It is the optimal speed for the unit to operate under the current wind speed.

[0030] Furthermore, the calculation of the active load reduction ΔP of each overspeed unit is performed. o_deli , as shown below:

[0031] ΔP o_deli =ΔPdelN ·a i (4);

[0032] When the overspeed units in the station cannot meet the station load reduction instruction requirements, calculate the remaining required load reduction active power ΔP del_r , as shown below:

[0033] ΔP del_r =ΔP delN -ΔP del_sum (5);

[0034] The remaining required load shedding active power ΔP del_r , calculate the standby active power ΔP of the j-th variable pitch unit p_delj , as shown below:

[0035]

[0036] Furthermore, the frequency regulation is performed by calculating the field control droop frequency regulation power instruction, giving priority to using the overspeed unit to allocate the frequency regulation power according to the standby ratio, and if the overspeed unit cannot meet the requirement, then the variable pitch unit is combined to evenly supplement the remaining frequency regulation power; including the following steps:

[0037] B1. The field control calculates the droop control frequency modulation power instruction ΔP based on the system frequency deviation Δf. f ;

[0038] B2. If the maximum active reserve of the overspeed unit ΔP del_sum ≥ΔP f , then calculate the frequency regulation weight coefficient b of each unit according to the proportion of standby power i and droop frequency modulation power ΔP o_fi , which can meet the station droop control requirements; the m overspeed units in the station are allocated droop frequency regulation power according to the proportion of standby power, and the frequency regulation weight coefficient of the i-th overspeed unit is defined as b i , calculate b i and the droop frequency modulation power ΔP allocated to the i-th overspeed unit o_fi

[0039] B3. If the maximum active reserve of the overspeed unit ΔP del_sum <ΔP f , calculate the FM power ΔP that needs to be supplemented f_r And the frequency modulation power ΔP allocated to each pitch unit p_fj ; Further obtain the droop frequency regulation power shortage ΔP that the variable pitch unit needs to supplement f_r , the frequency modulation power is distributed by evenly distributing each variable pitch unit, and the droop frequency modulation power shortage ΔP is calculated. f_r and the droop frequency modulation power ΔP allocated to the j-th variable pitch unit p_fj.

[0040] Furthermore, the frequency regulation weight coefficient b of the i-th overspeed unit i and the droop frequency modulation power ΔP allocated to the i-th overspeed unit o_fi As shown in the following formula:

[0041]

[0042] ΔP o_fi =-K pf Δf·P t b i (8)

[0043] Where: K pf is the wind turbine droop control coefficient, P t is the total active power output of the wind farm, ΔP o_deli It is the active load reduction of each overspeed unit.

[0044] Furthermore, the calculation obtains the droop frequency modulation power shortage ΔP f_r and the droop frequency modulation power ΔP allocated to the j-th variable pitch unit p_fj As shown in the following formula:

[0045] ΔP f_r =ΔP f -ΔP del_sum (9)

[0046]

[0047] Furthermore, the frequency modulation parameter adaptive control includes: calculating an adaptive curve of the wind turbine virtual inertia control coefficient based on the principle that the greater the frequency change rate, the greater the virtual inertia coefficient, as shown in the following formula:

[0048]

[0049] Where: K df is the wind farm virtual inertia control coefficient, K df_max and K df_min is the maximum and minimum value of the virtual inertia control coefficient, r db is the dead zone of system frequency change rate, df / dt is the system frequency change rate, K df_min is the minimum value of the inertia control coefficient, K df_max is the maximum value of the inertia control coefficient.

[0050] Furthermore, the frequency modulation parameter adaptive control further includes: calculating an adaptive curve of the droop control coefficient of the wind turbine generator set based on the principle that the larger the frequency deviation, the larger the droop control coefficient, as shown in the following formula:

[0051]

[0052] Where: K pf is the wind turbine droop control coefficient, K pf_max and K pf_min is the maximum and minimum value of the droop control coefficient, f db It is the system frequency modulation dead zone.

[0053] Furthermore, the frequency modulation parameter adaptive control further includes: performing secondary tuning on the virtual inertia control coefficient to compensate for the power shortage of the non-frequency modulation unit, as shown in the following formula:

[0054]

[0055] Where: P t_del It is the total active output power of the load-reducing units in the station.

[0056] Furthermore, the virtual inertia and droop overspeed control-based priority load shedding and frequency regulation, and the use of variable pitch units to supplement the power shortage, are based on the frequency regulation control method. Through overspeed control of the rotor speed, the wind turbine is operated on a suboptimal power curve to achieve load shedding. When the frequency drops, the rotor kinetic energy is released by reducing the speed to achieve conversion with electromagnetic power to achieve frequency regulation. When the frequency regulation power of the overspeed unit is less than the frequency regulation power demand of the station, the variable pitch unit increases the unit output power by adjusting and reducing the pitch angle, thereby supplementing the frequency regulation power shortage.

[0057] The combined supplementation of power shortages to complete the coordinated frequency regulation control of wind farm units and stations refers to combining the method of allocating load shedding and frequency regulation power, using overspeed control priority response, and pitch control to supplement the load shedding and frequency regulation power shortages to complete the coordinated frequency regulation control of wind farm units and stations.

[0058] Wind farm unit-station coordinated frequency regulation control device, including:

[0059] Adaptive frequency control architecture establishment module, used to establish a wind farm collaborative adaptive frequency control architecture based on overspeed control priority;

[0060] A setting module is used to determine, based on the control architecture and taking into account the adaptive control of frequency regulation parameters, whether virtual inertia control and droop control are configured in the unit-level frequency regulation controller and the station-level frequency regulation controller respectively;

[0061] A supplementary module is used to prioritize load shedding and frequency regulation based on virtual inertia and droop overspeed control, using variable pitch units to supplement power shortages;

[0062] The adaptive adjustment module is used to complete the wind farm unit-station coordinated frequency regulation control based on the adaptive control results of the frequency regulation parameters.

[0063] Furthermore, the load shedding control method is to calculate the field control load shedding instruction and determine the working range of each unit. Based on the principle of overspeed control priority, the rotor kinetic energy is used to evaluate and distribute the active reserve of each overspeed unit. If it is insufficient, the variable pitch control is used to evenly distribute the active reserve to achieve the station load shedding target, including the following steps:

[0064] A1. The wind farm central controller calculates the wind farm load shedding power reserve command value based on the site size and load shedding reserve requirements;

[0065] A2. Use the wind farm's load shedding power reserve command value and the operating status of each unit to allocate the load shedding power;

[0066] A3. Calculate the maximum active reserve capacity ΔP that all overspeed units can provide del_sum ;

[0067] A4. Compare the wind farm load shedding power reserve command value ΔP delN and the maximum active reserve ΔP in step A3 del_sum The size of ΔP del_sum <ΔP delN , then go to step A7, otherwise evaluate the load reduction capacity of each overspeed unit;

[0068] A5. If P del_sum ≥ΔP delN , then only the overspeed unit can meet the station load reduction requirements, and the load reduction capacity of each overspeed unit is evaluated using the rotor kinetic energy, where the load reduction capacity evaluation coefficient is calculated as a i ;

[0069] A7. When ΔP del_sum <ΔP delN When the overspeed unit is loaded down according to the maximum active reserve, the remaining required load reduction active power ΔP is calculated. del_r ;

[0070] A8. Using the average distribution method, for the remaining required load shedding active power ΔP del_r , calculate the standby active power ΔP of the j-th variable pitch unit p_delj .

[0071] A computer device comprises a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein when the processor executes the computer program, the steps of any one of the wind farm unit-station coordinated frequency regulation control methods are implemented.

[0072] A computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of any one of the wind farm unit-station coordinated frequency regulation control methods are implemented.

[0073] The present invention has the following beneficial effects and advantages:

[0074] Based on the shortcomings of the current typical station-level frequency regulation control, the present invention establishes a wind farm collaborative adaptive frequency regulation control architecture based on overspeed control priority, a wind farm unit-station collaborative frequency regulation control method based on overspeed control priority load reduction standby, priority frequency regulation response of overspeed units, and adaptive adjustment of frequency regulation control coefficients. This reduces the mechanical wear caused by the frequent operation of variable-pitch units, fully utilizes the frequency regulation performance of each unit, and improves the frequency regulation capability of the wind farm.

[0075] The present invention configures virtual inertia control and droop control in the unit-level and station-level frequency regulation controllers respectively, prioritizes load reduction and frequency regulation based on overspeed control, and supplements power shortages of variable-pitch units, and adaptively adjusts the frequency regulation coefficient, thereby realizing wind farm unit-station coordinated frequency regulation control.

[0076] The existing technical solutions fail to fully utilize the frequency regulation performance of each wind turbine in the station through a collaborative mechanism, fail to consider the mechanical wear caused by frequent pitch angle movements, and fail to dynamically adjust the frequency regulation control coefficient according to frequency disturbances, making it difficult to fully utilize the frequency regulation capability of the wind farm. The present invention fills this problem.

[0077] This invention improves wind farm load shedding by preferentially using turbines operating in the MPPT (maximum power point tracking) zone for overspeed control during the load shedding phase. This overspeed control reduces the frequency of pitch-shifting turbines, thereby reducing mechanical wear on the pitch angle control. Compared to prior art methods that rely on pitch-shifting turbines for load shedding, this invention significantly reduces the negative impact of pitch-shifting on turbine life, extending the turbine's useful life.

[0078] The present invention also optimizes frequency modulation power allocation. During the frequency modulation power allocation phase, the principle of prioritizing frequency modulation for overspeeding and load shedding units, with variable pitch control units providing auxiliary response, is combined with droop control and adaptive adjustment of the virtual inertia control coefficient. This prioritization of overspeeding units, combined with adaptive adjustment of the frequency modulation control coefficient, enables a fast and flexible frequency modulation response. Compared to the prior art control method of fixed frequency modulation coefficients, the present invention significantly improves the speed and accuracy of the frequency modulation response, raises the lowest frequency point, effectively suppresses rapid frequency changes, and enhances system stability.

[0079] This invention also optimizes the control strategy through a hierarchical approach, configuring virtual inertia control in the unit-level frequency controller and droop control in the station-level frequency controller, achieving hierarchical coordinated control. This leverages the rapid response of virtual inertia control while simultaneously achieving global power coordination through station-level droop control. Compared to existing approaches that do not employ hierarchical control strategies, this invention significantly improves the ability to rapidly withstand frequency disturbances and enhances the wind farm's ability to regulate grid frequency.

[0080] In summary, the present invention solves the problems of mechanical wear, slow frequency modulation response, insufficient frequency support capability, etc. existing in the prior art through improvements on the above-mentioned specific components and method steps, and significantly improves the frequency modulation performance and reliability of the wind farm. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0082] Figure 1 This is a schematic diagram of the wind farm coordinated frequency regulation principle of the present invention;

[0083] Figure 2 is a flow chart of wind farm coordinated load shedding according to the present invention;

[0084] Figure 3 This is a comparison diagram of response simulations under different variable pitch unit power allocation methods of the present invention;

[0085] Figure 4 is the actual wind farm topology adopted by the present invention;

[0086] Figure 5 It is a response simulation comparison diagram of various control methods under medium and high wind speed conditions of the present invention. DETAILED DESCRIPTION

[0087] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features therein can be combined with each other without conflict.

[0088] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0089] Refer to the following Figure 1-Figure 5 Describe the technical solutions of some embodiments of the present invention.

[0090] Example 1

[0091] The present invention provides an embodiment, which is a method for coordinated frequency regulation control of wind farm units and stations. Figure 1 As shown, Figure 1 yes Figure 1 This is a schematic diagram of the wind farm coordinated frequency regulation principle of the present invention.

[0092] Based on the shortcomings of typical station-level frequency regulation control, the present invention establishes a wind farm collaborative adaptive frequency regulation control architecture based on overspeed control priority. The present invention focuses on the coordinated load shedding and coordinated frequency regulation control strategy of wind farms, while taking into account the adaptive adjustment of frequency regulation parameters. Virtual inertia control and droop control are respectively set in the unit-level and station-level frequency regulation controllers. Based on overspeed control priority load shedding and frequency regulation, the variable pitch unit supplements the power shortage, and the frequency regulation coefficient is adaptively adjusted, thus realizing wind farm unit-station collaborative frequency regulation control.

[0093] A wind farm unit-station coordinated frequency regulation control method comprises the following steps:

[0094] Step 1. Establishing a wind farm coordinated adaptive frequency regulation control architecture based on overspeed control priority as an outline for guiding the specific load shedding and frequency regulation methods of the present invention;

[0095] Step 2. Using the wind farm coordinated load shedding and wind farm coordinated frequency regulation control methods in the control architecture established in Step 1, and considering the adaptive adjustment of frequency regulation parameters, determine the virtual inertia control and droop control settings in the unit-level and station-level frequency regulation controllers, respectively;

[0096] Step 3. Prioritize load shedding and frequency regulation based on virtual inertia and droop overspeed control, and use variable pitch units to supplement the power shortage. According to the frequency regulation control method of step 2, the wind turbine is operated on a suboptimal power curve through overspeed control of the rotor speed to achieve load shedding. When the frequency drops, the rotor kinetic energy is released by reducing the speed to achieve conversion with electromagnetic power to achieve the purpose of frequency regulation. When the frequency regulation power of the overspeed unit is less than the frequency regulation power demand of the station, the variable pitch unit increases the unit output power by adjusting and reducing the pitch angle, thereby supplementing the frequency regulation power shortage.

[0097] Step 4. Based on the result of the adaptive control of the frequency regulation parameters in step 2, the frequency regulation coefficient is adaptively adjusted. Combined with the method of allocating load shedding and frequency regulation power in step 3, overspeed control is used to give priority response, and pitch control is used to supplement the shortfall in load shedding and frequency regulation power, thus completing the wind farm unit-station coordinated frequency regulation control.

[0098] The wind farm coordinated load reduction control method based on overspeed control priority described in step 2 is to calculate the field control load reduction instruction and determine the working range of each unit, and then use the rotor kinetic energy to evaluate and distribute the active reserve of each overspeed unit based on the principle of overspeed control priority. If it is insufficient, variable pitch control is used to evenly distribute the active reserve to achieve the site load reduction target.

[0099] The wind farm coordinated load reduction control method comprises the following steps:

[0100] A1. The wind farm central controller calculates the wind farm load shedding power reserve command value ΔP based on the site scale and load shedding reserve requirements. delN It is equal to the load reduction reserve factor d% required by the station and the wind farm output active power P t The product of .

[0101] A2. After obtaining the wind farm load shedding power reserve command value, the load shedding power is allocated based on the operating status of each unit. Before allocating the load shedding power, it is necessary to first determine the operating range of each unit.

[0102] Based on wind turbine operating information collected by the supervisory control and data acquisition (SCADA) system, the operating range of each unit is determined according to the wind speed of the unit, namely the starting range, maximum power point tracking (MPPT) range, constant speed range, and constant power range. When the wind speed is between 3-6.05m / s, it is determined to be the starting range, 6.05-9.20m / s is determined to be the MPPT range, 9.20-10m / s is determined to be the constant speed range, and 10-22m / s is determined to be the constant power range.

[0103] The data acquisition and supervisory control SCADA is used to monitor and control each unit in the wind farm to collect operation data.

[0104] The maximum power point tracking (MPPT) is a control method that calculates the optimal power point by monitoring the voltage and current of a wind turbine in real time to ensure that the wind turbine always operates under optimal working conditions.

[0105] The overspeed control is a control method that reduces the unit output by increasing the speed when the fan is running on the MPPT curve, thereby obtaining active standby power.

[0106] The variable pitch control is a control method that optimizes the wind energy capture efficiency and ensures the stable operation of the wind turbine generator set by adjusting the angle of the wind turbine blades.

[0107] A3. Calculate the maximum active reserve capacity ΔP that all overspeed units can provide del_sum ;ΔPdel_sum is the sum of the maximum active reserves that all overspeed units can provide, ΔP del_maxi The maximum load shedding active power that can be achieved by overspeed control for the i-th wind turbine operating in the MPPT zone. Due to the rated speed limit, overspeed control only applies to the MPPT zone. Therefore, it is necessary to first identify the turbines operating in the MPPT zone based on the results of A2. Based on this, overspeed shedding control can be used to provide active power reserve for these turbines.

[0108] Based on the principle of overspeed control priority, assume that there are m units operating in the MPPT zone at the station. Calculate the maximum active reserve ΔP that these units can provide by using overspeed load reduction control. del_sum , as shown in formula (1):

[0109]

[0110] Where: ΔP del_maxi is the maximum load-shedding active power of the i-th unit in the wind farm operating in the MPPT zone.

[0111] A4. Compare the wind farm load reduction power reserve instruction value ΔP in step A1 delN and the maximum active reserve ΔP in step A3 del_sum The size of ΔP del_sum <ΔP delN , then go to step A7, otherwise evaluate the load reduction capacity of each overspeed unit;

[0112] A5. If in step A4, P del_sum ≥ΔP delN , then only the overspeed units can meet the load shedding standby requirements of the station. Therefore, in this case, the load shedding capacity of each overspeed unit is evaluated using the rotor kinetic energy, and the active load shedding amount is allocated. When the overspeed units in the station can meet the load shedding instruction requirements of the station, the calculation result of the overspeed unit load shedding capacity evaluation coefficient is a i .

[0113] The load shedding capacity assessment coefficient a of the i-th overspeed unit i It can be calculated by the maximum rotor kinetic energy that can be released by the i-th unit, as shown in equations (2) and (3):

[0114]

[0115] Where: ΔE k_max i is the maximum rotor kinetic energy that can be released by the i-th unit, J is the moment of inertia of the fan, ω N is the rated speed of the unit, ω opti It is the optimal speed for the unit to operate under the current wind speed.

[0116] A6. Using the load shedding capacity evaluation coefficient of the overspeed unit in A5, calculate the load shedding power ΔP of the wind farm. delN Distribute and calculate the active load reduction ΔP of each overspeed unit o_deli ;

[0117] Based on the overspeed unit load reduction capacity assessment coefficient, the active load reduction ΔP that should be allocated to each overspeed unit can be calculated. o_deli , calculated by formula (4):

[0118] ΔP o_deli =ΔP delN ·a i (4)

[0119] A7. The calculation in step A6 is for P del_sum ≥ΔP delN If the maximum active reserve ΔP del_sum <Wind farm load shedding power reserve command value ΔP delN , the overspeed unit shall reduce the load according to the maximum active reserve. When the overspeed unit in the station cannot meet the station load reduction instruction requirements, calculate the remaining required load reduction active power ΔP del_r ; As shown in formula (5):

[0120] ΔP del_r =ΔP delN -ΔP del_sum (5)

[0121] A8. Calculation result of the remaining required load shedding active power in step A7, ΔP del_r , using the average distribution method, calculate the standby active power ΔP of the j-th variable pitch unit p_delj .

[0122] At this time, the units operating in the constant speed area and constant power area need to reduce their load to make up for the load reduction power shortage. Assume that there are n units in the wind farm that are operating in the constant speed or constant power area. The rotor speed of these units has reached the rated speed ω. N Or upper speed limit ω max , load shedding can only be performed through pitch control, and the load shedding power is distributed evenly to the pitch units. The standby active power ΔP of the jth pitch unit is p_delj , as shown in formula (6):

[0123]

[0124] The wind farm coordinated frequency regulation based on overspeed control priority described in step 2 refers to calculating the field control droop frequency regulation power instruction and giving priority to allocating the frequency regulation power according to the standby ratio using the overspeed unit. If the overspeed unit cannot meet the requirements, the variable pitch unit is combined to evenly supplement the remaining frequency regulation power; frequency regulation parameter adaptive control: by setting the virtual inertia control and droop control in the unit-level and station-level frequency regulation controllers respectively, calculating the adaptive curves of the two respectively, and performing secondary tuning on the virtual inertia coefficient, so as to realize the adaptive adjustment of the frequency regulation control coefficient.

[0125] The wind farm coordinated frequency regulation control method comprises the following steps:

[0126] B1. The field control calculates the droop control frequency modulation power instruction ΔP based on the system frequency deviation Δf. f ;

[0127] Specifically, the station-level frequency regulation controller calculates the droop control frequency regulation power instruction ΔP according to the coordinated frequency deviation Δf f ;

[0128] B2. If the maximum active reserve of the overspeed unit ΔP del_sum ≥ΔP f , then calculate the frequency regulation weight coefficient b of each unit according to the proportion of standby power i and droop frequency modulation power ΔP o_fi ;

[0129] If the maximum active reserve of the overspeed unit ΔP del_sum ≥ΔP f , it means that the station droop control demand can be met by the response of the overspeed unit alone. The m overspeed units in the station allocate droop frequency modulation power according to the proportion of standby power, and define the frequency modulation weight coefficient of the i-th overspeed unit as b i , b can be calculated by equations (7) and (8) i and the droop frequency modulation power ΔP allocated to the i-th overspeed unit o_fi ;

[0130]

[0131] ΔP o_fi =-K pf Δf·P t b i (8)

[0132] Where: K pf is the wind turbine droop control coefficient, P t is the total active power output of the wind farm, ΔP o_deli is the active load reduction of each overspeed unit;

[0133] B3. If the maximum active reserve of the overspeed unit ΔP del_sum <ΔP f , calculate the FM power ΔP that needs to be supplemented f_r And the frequency modulation power ΔP allocated to each pitch unit p_fj .

[0134] If the maximum active reserve of the overspeed unit ΔP del_sum <ΔP f , then the variable pitch unit needs to participate in the frequency regulation. At this time, all overspeed units respond according to their own active frequency regulation upper limit, that is, the sum of the frequency regulation power of all overspeed units is ΔP del_sum , and further obtain the droop frequency regulation power shortage ΔP that the variable pitch unit needs to supplement f_r , the frequency modulation power is distributed by evenly dividing each pitch unit, and the frequency modulation power shortage ΔP is reduced. f_r and the droop frequency modulation power ΔP allocated to the j-th variable pitch unit p_fj As shown in formula (9) and formula (10):

[0135] ΔP f_r =ΔP f -ΔP del_sum (9)

[0136]

[0137] In the wind farm unit-station coordinated frequency regulation control method of the present invention, the virtual inertia control coefficient and the droop control coefficient both adopt adaptive control that can be dynamically adjusted according to the magnitude of the frequency disturbance, and include the following steps:

[0138] C1. Calculate the adaptive curve of the virtual inertia control coefficient based on the principle that the greater the frequency change rate, the greater the virtual inertia coefficient.

[0139] The adaptive curve of the virtual inertia control coefficient of the wind turbine is shown in formula (11):

[0140]

[0141] Where: K df is the wind farm virtual inertia control coefficient, K df_max and K df_min is the maximum and minimum value of the virtual inertia control coefficient, r db K is the dead zone of system frequency change rate, df_max , K df_min and r db All are obtained with reference to the national standard GB / T19963.1-2021, df / dt is the system frequency change rate, K df_min is the minimum value of the inertia control coefficient, K df_max is the maximum value of the inertia control coefficient.

[0142] C2. Calculate the adaptive curve of the droop control coefficient based on the principle that the larger the frequency deviation, the larger the droop control coefficient.

[0143] The adaptive curve of the wind turbine droop control coefficient is shown in formula (12):

[0144]

[0145] Where: K pf is the wind turbine droop control coefficient, K pf_max and K pf_min is the maximum and minimum value of the droop control coefficient, f db is the system frequency modulation dead zone, K pf_max , K pf_min and f db All are obtained with reference to the national standard GB / T 19963.1-2021.

[0146] C3. Perform secondary tuning on the virtual inertia control coefficient to compensate for the power shortage of the non-frequency regulating units.

[0147] In order to compensate for the frequency regulation power shortage of the units not participating in the frequency regulation for the virtual inertia control, the virtual inertia control coefficient is adjusted twice on the basis of adaptive adjustment. The adjusted virtual inertia control coefficient K' df As shown in formula (13):

[0148]

[0149] Where: P t_del It is the total active output power of the load-reducing units in the station.

[0150] Example 2

[0151] The present invention further provides an embodiment, which is a wind farm unit-station coordinated frequency regulation control method.

[0152] More specifically, Figure 1 As shown, the present invention establishes a wind farm collaborative adaptive frequency control architecture based on overspeed control priority: the station-level frequency controller receives the operating information of each unit, and sends the secondary setting virtual inertia control coefficient, load reduction power and droop power command value to each unit. At the same time, the unit-level frequency controller performs virtual inertia response, realizing collaborative frequency control of the wind farm.

[0153] according to Figure 2 As shown, the steps of the wind farm coordinated load reduction control method are as follows:

[0154] A1. The wind farm central controller calculates the wind farm load shedding power command value ΔP based on the site scale and load shedding reserve requirements. delN ;

[0155] A2. Based on the station operation data collected by the SCADA system, determine the operating status of each unit, i.e., whether it is operating in the start-up zone, MPPT zone, constant speed zone, or constant power zone;

[0156] A3. For units operating in the MPPT zone, overspeed load reduction control can be used to reduce the load of the unit by increasing the rotor speed. W When the fan rotor is running at an overspeed, the range of the fan rotor overspeed is the optimal speed ω when it runs on the MPPT curve. opt To rated speed ω N From this, the maximum load-shedding active power ΔP of the i-th unit in the wind farm operating in the MPPT zone can be calculated. del_maxi :

[0157] ΔP del_maxi =P opti -P del_maxi (1)

[0158]

[0159] Where, P opti The unit is at the current wind speed V Wi Run at the optimal speed ω opti Active power at time , P del_maxi The unit is running at the rated speed ω under the current wind speed N The active power at the time of maximum load reduction is ρ, which is the active power at the time of maximum load reduction. ρ is the air density, R is the radius of the wind wheel, and C p_max and C p_del_maxi are the maximum wind energy utilization rate of the unit and the wind energy utilization rate at maximum load reduction, λ opti and λ del_maxi They are the optimal tip speed ratio of the unit and the tip speed ratio at maximum standby.

[0160] Assuming that there are m wind turbines operating in the MPPT zone in the wind farm, the maximum active reserve ΔP of the m wind turbines in the wind farm using overspeed control can be calculated according to this method. del_sum :

[0161]

[0162] A4. If ΔP del_sum ≥ΔP delN , indicating that the overall load shedding requirement of the wind farm can be met by simply relying on overspeed load shedding of units operating in the MPPT zone. In this case, the rotor kinetic energy can be used to evaluate the load shedding capacity of each overspeed unit and allocate active load shedding capacity;

[0163] A5. The maximum rotor kinetic energy ΔE that can be released by the i-th unitk_maxi for:

[0164]

[0165] Where J is the fan's moment of inertia.

[0166] Define the load reduction capacity evaluation coefficient a of the i-th overspeed unit i :

[0167]

[0168] Where: J is the moment of inertia of the fan, ω N is the rated speed of the unit, ω opti It is the optimal speed for the unit to operate under the current wind speed.

[0169] A6. Based on the overspeed unit load reduction capacity assessment coefficient, the active load reduction ΔP of each overspeed load reduction unit can be calculated o_deli :

[0170] ΔP o_deli =ΔP delN ·a i (6)

[0171] A7. When ΔP del_sum <ΔP delN When the load of the units operating in the constant speed area and the constant power area is reduced to make up for the load reduction power shortage. Assume that there are n units in the wind farm that are operating in the constant speed or constant power area. The rotor speed of these units has reached the rated speed ω. N Or upper speed limit ω max , load shedding can only be performed through pitch control. At this time, the load shedding power shortage ΔP del_r It can be expressed as:

[0172] ΔP del_r =ΔP delN -ΔP del_sum (7)

[0173] A8. Three theoretical methods are proposed for allocating load shedding power for pitch-controlled units:

[0174] Type 1. Based on load reduction power ΔP del_r and the actual wind speed of each unit, so that all variable pitch units adjust the same pitch angle to achieve load reduction;

[0175] The second method is to quantify the wear of the mechanical parts of each unit during pitch control, and allocate load shedding power with the goal of minimizing the total mechanical wear of the wind farm;

[0176] Type 3: n variable pitch units evenly share the load shedding power shortage.

[0177] However, the first method is difficult to ensure that the pitch angle β of each unit is adjusted to the same exact value in engineering applications; the calculation of mechanical wear in the second method is too cumbersome. Therefore, the third method is more reasonable and easy to implement. The present invention adopts the method of evenly dividing the load reduction power for units operating in the constant speed and constant power area. The standby active power ΔP of the jth variable pitch unit p_delj It can be expressed as:

[0178]

[0179] At this point, a wind farm coordinated load reduction control method based on overspeed control priority has been formed, on this basis, wind farm coordinated frequency regulation control can be carried out.

[0180] After calculating the frequency modulation power command value, the station-level droop control calculates the active power regulation for each unit based on the power allocation module. Similar to the wind farm coordinated load reduction method proposed in this paper, station-level droop frequency modulation control also prioritizes the use of overspeeding units for frequency modulation response to reduce mechanical wear caused by pitch control.

[0181] The specific steps of the wind farm coordinated frequency regulation control method are as follows:

[0182] B1. The station-level frequency regulation controller calculates the station's droop control frequency regulation power instruction ΔP based on the coordinated frequency deviation Δf f ;

[0183] B2. If the total standby power of the overspeed unit ΔP del_sum ≥ΔP f , it means that the station droop control demand can be met by the response of the overspeed unit alone. The m overspeed units in the station allocate droop frequency modulation power according to the proportion of standby power, and define the frequency modulation weight coefficient of the i-th overspeed unit as b i :

[0184]

[0185] Then the droop frequency modulation power ΔP allocated to the i-th overspeed control unit is o_fi for:

[0186] ΔP o_fi =-K pf Δf·P t b i (10)

[0187] Where: K pf is the wind turbine droop control coefficient, P t Total active power output for the wind farm;

[0188] B3. If the overspeed unit's standby power ΔP del_sum <ΔP f, then the variable pitch unit needs to participate in the frequency regulation. At this time, all overspeed units respond according to their own active frequency regulation upper limit, that is, the sum of the frequency regulation power of all overspeed units is ΔP del_sum , and further obtain the droop frequency regulation power shortage ΔP that the variable pitch unit needs to supplement f_r :

[0189] ΔP f_r =ΔP f -ΔP del_sum (11)

[0190] There are four main options for allocating power to variable-pitch generator sets:

[0191] Solution 1: The unit with lower wind speed will be activated first;

[0192] Option 2: The higher wind speed unit will be activated first;

[0193] Option 3: Each unit equally shares the frequency modulation power;

[0194] Scheme 4: Allocate frequency modulation power to each unit according to its steady-state output weight.

[0195] In order to optimize the frequency regulation performance, the above four frequency regulation power allocation methods were compared under the condition that each variable pitch unit was in 10% load reduction standby mode. The simulation results were as follows using the MATLAB / Simulink platform: Figure 3 The results show that when each variable pitch unit evenly distributes the frequency regulation power, the system frequency regulation performance is optimal, so the droop frequency regulation power ΔP allocated to the jth variable pitch unit is p_fj for:

[0196]

[0197] At this point, a wind farm coordinated frequency control method based on overspeed control priority has been formed, on this basis, adaptive adjustment of the frequency control coefficient can be added.

[0198] Considering that traditional fixed parameter control does not fully utilize the control flexibility of power electronic equipment and cannot adapt to different degrees of disturbance conditions, the present invention introduces a dynamic coefficient and uses a parameter adaptive adjustment method to further improve the frequency regulation performance of the wind farm.

[0199] In the wind farm unit-station coordinated frequency regulation control method based on overspeed control priority, both the virtual inertia control coefficient and the droop control coefficient adopt adaptive control that can be dynamically adjusted according to the magnitude of the frequency disturbance. The specific steps of the frequency regulation coefficient adaptive control are as follows:

[0200] C1. According to the national standard GB / T 19963.1-2021, the frequency modulation power ΔP output by wind power virtual inertia control df for:

[0201]

[0202] Where, T J is the equivalent inertia time constant of the wind farm, P t For the station to make active contribution, f N is the rated frequency of the power system.

[0203] Therefore, the wind power virtual inertia control coefficient K df It can be expressed as:

[0204]

[0205] Based on the principle that the greater the frequency change rate, the greater the virtual inertia coefficient, the adaptive curve of the virtual inertia control coefficient of the wind turbine proposed in the present invention is as follows:

[0206]

[0207] In the formula, the maximum value of the inertia control coefficient K df_max and minimum value K df_min According to the national standard GB / T 19963.1-2021 combined with step C1 formula (14), they are K df_max =0.24, K df_min =0.16. r db The dead zone of the system frequency change rate is 0.1 Hz / s according to the national standard GB / T 19963.1-2021.

[0208] C2. According to the national standard GB / T 19963.1-2021, the droop control output frequency modulation power ΔP pf for:

[0209]

[0210] Where K f is the active frequency regulation coefficient corresponding to the wind turbine.

[0211] Therefore, the wind turbine droop control coefficient K pf It can be expressed as:

[0212]

[0213] Similar to the above virtual inertia coefficient, the wind farm droop adaptive curve proposed in the present invention is as follows:

[0214]

[0215] Where K pf is the wind turbine droop control coefficient, and the maximum droop coefficient K pf_maxand minimum value K pf_min According to the national standard GB / T 19963.1-2021 and combined with C2 formula (17), they are K pf_max =1,K pf_min =0.2; f db The dead zone of frequency modulation for droop control is 0.05 Hz according to the national standard GB / T 19963.1-2021.

[0216] C3. Considering that some units in the station may not participate in the system frequency regulation due to too low speed, in order to compensate for the virtual inertia deficiency of this part, the present invention further proposes a secondary setting link of the virtual inertia coefficient based on the above adaptive adjustment. Suppose the total active power of the load-reduced operating unit is P t_del , then the virtual inertia coefficient after secondary tuning is:

[0217]

[0218] Where: P t_del It is the total active output power of the load-reducing units in the station.

[0219] Example 3

[0220] The present invention further provides an embodiment, which is a wind farm unit-station coordinated frequency regulation control method.

[0221] In order to verify the effectiveness of the wind farm unit-station coordinated frequency regulation control method based on overspeed control priority proposed in Example 1 and Example 2, based on Figure 4 The topology shown builds an electromagnetic transient model of a grid-following direct-drive wind farm. The specific parameters are shown in Table 1.

[0222] Table 1 Main parameters of the system

[0223] Parameter name Parameter value Rated voltage 220kV Rated frequency 50Hz Synchronous machine capacity 100MVA Synchronous machine inertia time constant 3s Synchronous machine adjustment coefficient 0.05 Synchronous machine frequency modulation dead zone ±0.033Hz Wind farm capacity 100MVA load capacity 100MVA

[0224] Taking the wind farm average wind speed of 8.95m / s and 5MW load sudden increase as typical working conditions, the frequency modulation response curves of the proposed method, various traditional coordinated control methods and the unit's own response are compared using the MATLAB / Simulink platform. Figure 5 The simulation results show that the overall frequency deviation and frequency change rate of the system after the disturbance occurs are significantly reduced. The lowest frequency point is increased by up to 0.07Hz compared with the traditional method, and the absolute value of the maximum frequency change rate is reduced by up to 0.02Hz / s. At the same time, the action of the variable pitch unit is reduced, which proves the effectiveness of the method of the present invention.

[0225] Example 4

[0226] The present invention further provides an embodiment, which is a wind farm unit-station coordinated frequency regulation control device, comprising:

[0227] An adaptive frequency control architecture establishment module is used to establish a wind farm collaborative adaptive frequency control architecture based on overspeed control priority. This architecture serves as a reference outline for the subsequent load shedding and frequency regulation power allocation strategies for wind farms in the present invention.

[0228] The setting module refers to the wind farm coordinated load reduction and wind farm coordinated frequency regulation control methods in the established adaptive frequency regulation control architecture, considers the adaptive control of frequency regulation parameters, and sets virtual inertia control and droop control in the unit-level and station-level frequency regulation controllers respectively;

[0229] The supplementary module is used to prioritize load shedding and frequency regulation based on overspeed control, and to supplement the power shortage of the variable-pitch unit. According to the frequency regulation control method of step 2, the wind turbine is operated on a suboptimal power curve through overspeed control of the rotor speed to achieve load shedding. When the frequency drops, the rotor kinetic energy is released by reducing the speed to achieve conversion with electromagnetic power to achieve the purpose of frequency regulation. When the frequency regulation power of the overspeed unit is less than the frequency regulation power demand of the station, the variable-pitch unit increases the unit output power by adjusting and reducing the pitch angle, thereby supplementing the frequency regulation power shortage.

[0230] The adaptive adjustment module is used to adaptively adjust the frequency regulation coefficient according to the results of the adaptive control of the medium frequency regulation parameters. Combined with the method of allocating load shedding and frequency regulation power, it uses overspeed control to give priority response and pitch control to supplement the load shedding and frequency regulation power shortage, thus completing the wind farm unit-station coordinated frequency regulation control.

[0231] The wind farm unit-station coordinated frequency regulation control device based on overspeed control priority is used to implement the steps of the wind farm unit-station coordinated frequency regulation control method described in Example 1 or 2.

[0232] Example 5

[0233] Based on the same inventive concept, an embodiment of the present invention further provides a computer device comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor. When the processor executes the computer program, the steps of any of the wind farm unit-station coordinated frequency regulation control methods described in Embodiments 1 or 2 are implemented.

[0234] Example 6

[0235] Based on the same inventive concept, an embodiment of the present invention further provides a computer storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the wind farm unit-station coordinated frequency regulation control methods described in Example 1 or 2 are implemented.

[0236] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0237] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0238] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0239] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0240] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A wind farm unit-station coordinated frequency regulation control method, characterized by: include: Establish a wind farm collaborative adaptive frequency control architecture based on overspeed control priority; Based on the control architecture and considering the adaptive control of frequency regulation parameters, it is determined that virtual inertia control and droop control are configured in the unit-level frequency regulation controller and the station-level frequency regulation controller respectively; Prioritize load shedding and frequency regulation based on virtual inertia and droop overspeed control, and use variable pitch units to supplement power shortages; According to the adaptive control results of the frequency regulation parameters, pitch control supplements the load shedding and frequency regulation power shortage, completing the wind farm unit-station coordinated frequency regulation control.

2. The wind farm unit-station coordinated frequency regulation control method according to claim 1 is characterized by: The load reduction is achieved by calculating the load reduction instructions of the field control and judging the working range of each unit. Based on the principle of overspeed control priority, the active reserve of each overspeed unit is evaluated and distributed using the rotor kinetic energy. If it is insufficient, the active reserve is evenly distributed using pitch control to achieve the station load reduction target. The steps include: A1. The wind farm central controller calculates the wind farm load shedding power reserve command value based on the site size and load shedding reserve requirements; A2. Use the wind farm's load shedding power reserve command value and allocate the load shedding power based on the operating status of each unit; A3. Calculate the maximum active reserve ΔP provided by all overspeed units del_sum ; A4. Compare the wind farm load shedding power reserve command value ΔP delN and the maximum active reserve ΔP in step A3 del_sum The size of ΔP del_sum <ΔP delN , then go to step A7, otherwise evaluate the load shedding capacity of each overspeed unit; A5. If P del_sum ≥ΔP delN , then only the overspeed units can meet the station load reduction requirements, and the load reduction capacity of each overspeed unit is evaluated using the rotor kinetic energy; A6. When P del_sum ≥ΔP delN When the load shedding capacity evaluation coefficient of the overspeed unit is used, the load shedding power ΔP of the wind farm is calculated. delN Make an allocation; A7. When ΔP del_sum <ΔP delN When the overspeed unit is deloaded according to the maximum active reserve, the remaining required load shedding active power is calculated; A8. Using the average distribution method, for the remaining required load shedding active power ΔP del_r , calculate the standby active power of the j-th variable pitch unit.

3. The wind farm unit-station coordinated frequency regulation control method according to claim 2 is characterized by: The maximum active reserve capacity ΔP that all overspeed units can provide del_sum , as shown below: Where: ΔP del_maxi is the maximum load-shedding active power of the i-th unit in the wind farm operating in the MPPT zone.

4. The wind farm unit-station coordinated frequency regulation control method according to claim 2 is characterized by: The calculation result of the load reduction capacity evaluation coefficient is a i , the load shedding capacity assessment coefficient a of the i-th overspeed unit i The maximum rotor kinetic energy that can be released by the i-th unit is calculated as shown in equations (2) and (3): Where: ΔE k_maxi is the maximum rotor kinetic energy that can be released by the i-th unit, J is the moment of inertia of the fan, ω N is the rated speed of the unit, ω opti It is the optimal speed for the unit to operate under the current wind speed.

5. The wind farm unit-station coordinated frequency regulation control method according to claim 2 is characterized by: The calculation of active load reduction ΔP of each overspeed unit o_deli , as shown below: ΔP o_deli =ΔP delN ·a i (4); When the overspeed units in the station cannot meet the station load reduction instruction requirements, calculate the remaining required load reduction active power ΔP del_r , as shown below: ΔP del_r =ΔP delN -ΔP del_sum (5); The remaining required load shedding active power ΔP del_r , calculate the standby active power ΔP of the j-th variable pitch unit p_delj , as shown below:

6. The wind farm unit-station coordinated frequency regulation control method according to claim 1, characterized in that: The frequency regulation is to calculate the field control droop frequency regulation power instruction, give priority to using the overspeed unit to distribute the frequency regulation power according to the standby ratio, and if the overspeed unit cannot meet the requirement, then the variable pitch unit is combined to evenly supplement the remaining frequency regulation power; including the following steps: B1. The field control calculates the droop control frequency modulation power instruction ΔP based on the system frequency deviation Δf. f ; B2. If the maximum active reserve of the overspeed unit ΔP del_sum ≥ΔP f , then calculate the frequency regulation weight coefficient b of each unit according to the proportion of standby power i and droop frequency modulation power ΔP o_fi , which can meet the station droop control requirements; the m overspeed units in the station are allocated droop frequency regulation power according to the proportion of standby power, and the frequency regulation weight coefficient of the i-th overspeed unit is defined as b i , calculate b i and the droop frequency modulation power ΔP allocated to the i-th overspeed unit o_fi B3. If the maximum active reserve of the overspeed unit ΔP del_sum <ΔP f , calculate the FM power ΔP that needs to be supplemented f_r And the frequency modulation power ΔP allocated to each pitch unit p_fj ; Further obtain the droop frequency regulation power shortage ΔP that the pitch unit needs to supplement f_r , the frequency modulation power is distributed by evenly distributing each variable pitch unit, and the droop frequency modulation power shortage ΔP is calculated. f_r and the droop frequency modulation power ΔP allocated to the j-th variable pitch unit p_fj .

7. The wind farm unit-station coordinated frequency regulation control method according to claim 6 is characterized by: The frequency regulation weight coefficient b of the i-th overspeed unit i and the droop frequency modulation power ΔP allocated to the i-th overspeed unit o_fi As shown in the following formula: ΔP o_fi =-K pf Δf·P t ·b i (8) Where: K pf is the wind turbine droop control coefficient, P t is the total active power output of the wind farm, ΔP o_deli It is the active load reduction of each overspeed unit.

8. The wind farm unit-station coordinated frequency regulation control method according to claim 6 is characterized by: The calculation results in the droop frequency modulation power deficit ΔP f_r and the droop frequency modulation power ΔP allocated to the j-th variable pitch unit p_fj As shown in the following formula: ΔP f_r =ΔP f -ΔP del_sum (9) 9. The wind farm unit-station coordinated frequency regulation control method according to claim 1, characterized in that: The frequency modulation parameter adaptive control includes: calculating an adaptive curve of the wind turbine virtual inertia control coefficient based on the principle that the greater the frequency change rate, the greater the virtual inertia coefficient, as shown in the following formula: Where: K df is the wind farm virtual inertia control coefficient, K df_max and K df_min is the maximum and minimum value of the virtual inertia control coefficient, r db is the dead zone of system frequency change rate, df / dt is the system frequency change rate, K df_min is the minimum value of the inertia control coefficient, K df_max is the maximum value of the inertia control coefficient.

10. The wind farm unit-station coordinated frequency regulation control method according to claim 1, characterized in that: The frequency modulation parameter adaptive control further includes: calculating an adaptive curve of the droop control coefficient of the wind turbine generator set based on the principle that the larger the frequency deviation, the larger the droop control coefficient, as shown in the following formula: Where: K pf is the wind turbine droop control coefficient, K pf_max and K pf_min is the maximum and minimum value of the droop control coefficient, f db It is the system frequency modulation dead zone.

11. The wind farm unit-station coordinated frequency regulation control method according to claim 1, characterized in that: The frequency modulation parameter adaptive control further includes: performing secondary tuning on the virtual inertia control coefficient to compensate for the power shortage of the non-frequency modulation unit, as shown in the following formula: Where: P t_del It is the total active output power of the load-reducing units in the station.

12. The wind farm unit-station coordinated frequency regulation control method according to claim 1, characterized in that: The virtual inertia and droop overspeed control give priority to load shedding and frequency regulation, and use the variable pitch unit to supplement the power shortage. This is based on the frequency regulation control method. Through the overspeed control of the rotor speed, the wind turbine is operated on the suboptimal power curve to achieve load shedding. When the frequency drops, the rotor kinetic energy is released by reducing the speed to achieve conversion with electromagnetic power to achieve frequency regulation. When the frequency regulation power of the overspeed unit is less than the frequency regulation power demand of the station, the variable pitch unit increases the unit output power by adjusting and reducing the pitch angle, thereby supplementing the frequency regulation power shortage. The combined supplementation of power shortages to complete the coordinated frequency regulation control of wind farm units and stations refers to combining the method of allocating load shedding and frequency regulation power, using overspeed control priority response, and pitch control to supplement the load shedding and frequency regulation power shortages to complete the coordinated frequency regulation control of wind farm units and stations.

13. A wind farm unit-station coordinated frequency regulation control device, characterized by: include: Adaptive frequency control architecture establishment module, used to establish a wind farm collaborative adaptive frequency control architecture based on overspeed control priority; A setting module is used to determine, based on the control architecture and taking into account the adaptive control of frequency regulation parameters, whether virtual inertia control and droop control are configured in the unit-level frequency regulation controller and the station-level frequency regulation controller respectively; A supplementary module is used to prioritize load shedding and frequency regulation based on virtual inertia and droop overspeed control, using variable pitch units to supplement power shortages; The adaptive adjustment module is used to complete the wind farm unit-station coordinated frequency regulation control based on the adaptive control results of the frequency regulation parameters.

14. The wind farm unit-station coordinated frequency regulation control device according to claim 13, characterized in that: The load shedding control method is to calculate the field control load shedding instruction and determine the working range of each unit. Based on the principle of overspeed control priority, the rotor kinetic energy is used to evaluate and distribute the active reserve of each overspeed unit. If it is insufficient, the variable pitch control is used to evenly distribute the active reserve to achieve the station load shedding target, including the following steps: A1. The wind farm central controller calculates the wind farm load shedding power reserve command value based on the site size and load shedding reserve requirements; A2. Use the wind farm's load shedding power reserve command value and allocate the load shedding power based on the operating status of each unit; A3. Calculate the maximum active reserve capacity ΔP that all overspeed units can provide del_sum ; A4. Compare the wind farm load shedding power reserve command value ΔP delN and the maximum active reserve ΔP in step A3 del_sum The size of ΔP del_sum <ΔP delN , then go to step A7, otherwise evaluate the load reduction capacity of each overspeed unit; A5. If P del_sum ≥ΔP delN , then only the overspeed unit can meet the station load reduction requirements, and the load reduction capacity of each overspeed unit is evaluated using the rotor kinetic energy, where the load reduction capacity evaluation coefficient is calculated as a i ; A7. When ΔP del_sum <ΔP delN When the overspeed unit is loaded down according to the maximum active reserve, the remaining required load reduction active power ΔP is calculated. del_r ; A8. Using the average distribution method, for the remaining required load shedding active power ΔP del_r , calculate the standby active power ΔP of the j-th variable pitch unit p_delj .

15. A computer device comprising a storage medium, a processor, and a computer program stored in the storage medium and executable on the processor, wherein: When the processor executes the computer program, the steps of the wind farm unit-station coordinated frequency regulation control method according to any one of claims 1 to 12 are implemented.

16. A computer storage medium, characterized by: The computer storage medium stores a computer program, which, when executed by a processor, implements the steps of the wind farm unit-station coordinated frequency regulation control method according to any one of claims 1 to 12.

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