Primary frequency modulation method based on maximum and minimum points of power grid frequency response

Abstract

The application discloses a fan primary frequency modulation method based on a maximum or minimum value point time of a power grid frequency response, and comprises the following steps: detecting whether a frequency event occurs and recording the time when the frequency event occurs; calculating the minimum value point time of the power grid frequency response under a step load power excitation; analyzing the relationship between the maximum value point time of the power grid frequency response under a TLIC wind power excitation and the minimum value point time of the power grid frequency response under the step load power excitation; estimating the maximum value point time of the power grid frequency response under the TLIC wind power excitation, and calculating the delay start time of the fan TLIC method based on a maximum or minimum value point time corresponding principle; and realizing the fan primary frequency modulation control based on the maximum or minimum value point time corresponding principle according to the delay start time. The method can realize the correspondence between the maximum value point of the frequency response under the TLIC wind power excitation and the minimum value point under the load sudden increase, further improve the minimum point of the power grid frequency, and improve the frequency modulation effect of the fan participating in the power grid.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine control, and in particular to a wind turbine primary frequency regulation control method and system based on the peak value of the power grid frequency response. Background Technology

[0002] With the significant increase in wind power penetration, the proportion of conventional synchronous turbines is continuously decreasing, and the power system inertia is significantly reduced, making it urgent for wind turbines to participate in the primary frequency regulation of the power grid. Based on whether the output electromagnetic power of the wind turbine is related to the grid frequency, existing wind turbine primary frequency regulation control can be roughly divided into two categories: primary frequency regulation control that responds to frequency changes in real time, such as virtual inertial control and droop control; and primary frequency regulation control with preset power curves, such as step inertial control (SIC) and torque-limited inertial control (TLIC).

[0003] Primary frequency control based on a preset power curve generally includes two stages: frequency support and turbine speed recovery. When a sudden load surge occurs, the SiC method increases wind power in a step manner to support the active power balance of the grid. From the perspective of grid frequency response superposition compensation alone, the step increase in wind power provides the best compensation effect for the load surge during the frequency support stage. In particular, if the increase in wind power is equal to the load surge, the frequency response component corresponding to the wind power during the frequency support stage will completely compensate for the grid frequency drop caused by the load surge, i.e., the grid frequency remains constant.

[0004] However, due to the limited kinetic energy of the wind turbine buffer, the SIC method's step reduction of wind power at the end of frequency support leads to the well-known secondary frequency drop (SFD) in the power grid. Therefore, how to coordinate the primary frequency regulation of wind turbines and synchronous generators to mitigate the secondary frequency drop has become a focus of existing research. The main progress can be summarized in two aspects: improved methods based on SIC and methods that exhibit a gradual decrease in wind power. However, the application of the TLIC method essentially changes the type of wind power change, no longer exhibiting the same step form as a load surge. Furthermore, the maximum value of the frequency response component obtained by the TLIC method always precedes the minimum value of the load surge, causing the maximum effect of wind turbine frequency regulation on power grid frequency support to occur prematurely, resulting in insufficient compensation for the power grid frequency drop caused by the load surge. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a wind turbine primary frequency regulation control method and system based on the time difference between the maximum and minimum values ​​of the grid frequency response. This method is based on estimating the time difference between the maximum and minimum values ​​of the frequency response components. By delaying the start-up time of the wind turbine's TLIC method, it achieves the correspondence between the maximum value point of the frequency response under TLIC wind power excitation and the minimum value point under load surge, further improving the minimum grid frequency and enhancing the wind turbine's participation in grid frequency regulation.

[0006] The technical solution to achieve the objective of this invention is: a method for primary frequency regulation of wind turbines based on the extreme point of the power grid frequency response, the method comprising the following steps:

[0007] Step 1: Detect frequency events and record the occurrence time t0;

[0008] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0009] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0010] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0011] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0012] Further, step 1 specifically involves: detecting the power grid frequency deviation; if it exceeds a preset threshold |Δf| thd If the event occurs, it is considered that a sudden increase in load or generator tripping event has occurred in the power grid, i.e., a frequency event, and the occurrence time t0 is recorded.

[0013] Furthermore, step 2 involves calculating the minimum point of the grid frequency response under step load power excitation. The specific process includes:

[0014] For a load surge event, the grid frequency response Δf under step load power excitation L for:

[0015] Δf L (t)=ΔP L h step (t)

[0016]

[0017]

[0018] In the formula, ΔP L H is the load step disturbance amplitude, D is the system inertia time constant, R is the governor droop coefficient, T is the governor time constant, F is the proportion of high-pressure turbine power to total turbine power, and K is the mechanical power gain coefficient.

[0019] The time of minimum point of the grid frequency response under step load power excitation is:

[0020]

[0021] Furthermore, step 3, which involves obtaining the relationship between the time of the maximum value of the grid frequency response under torque-limited inertial control (TLIC) wind power excitation and the time of the minimum value of the grid frequency response under step load power excitation, specifically includes:

[0022] Simplified approximate grid frequency response Δf under TLIC wind power excitation W As shown in the following equation, it can be represented as the superposition of the frequency responses of a step signal and two ramp signals:

[0023] Δf W (t)=ΔP W0 h step (t)u(t)+K P-t h ramp (t)u(t)-K P-t h ramp (t-t1)u(t-t1)

[0024] In the formula, ΔP W0 For the initial support power increment of the wind turbine TLIC method, ΔP W0 =P Tlim (ω0)-P W0 P Tlim (ω0) represents the power of the maximum torque at the initial speed ω0, P W0 K represents the initial electromagnetic power of the wind turbine. P-t t is the slope of the piecewise curve, i.e., the rate of change of wind power; t1 is the time it takes for the simplified wind power to decrease to the electromagnetic power at the equilibrium point; u(t) is the unit step signal, h step (t) represents the unit step response, h ramp (t) represents the unit slope response;

[0025] Differentiating the above equation, we obtain the simplified frequency response rate corresponding to TLIC wind power:

[0026]

[0027] By analyzing Δf' W (t) in The symbols at each point indicate the time of the maximum value of the power grid frequency response. The time of minimum frequency response of the power grid The relationship between the two is based on t1 and The relationship can be divided into the following two cases:

[0028] (1) When Sometimes,

[0029]

[0030] because and K P-t <0, therefore

[0031] (2) When Sometimes,

[0032]

[0033] Because h step (t) in It is increasing, and at the same time so

[0034] therefore, This holds true under TLIC wind power excitation with arbitrary parameters, Δf W (t) in If there exists at least one maximum point within the range, and the first maximum point is also the maximum point, then:

[0035]

[0036] Furthermore, step 4 specifically includes:

[0037] Step 4-1: Based on the simplified TLIC wind power output, the Newton-Raphson method is used to numerically solve for the result. Estimated value;

[0038] Step 4-2: Calculate the delayed start-up time of the wind turbine using the TLIC method.

[0039]

[0040] Furthermore, step 5 specifically includes: based on the estimated delay startup time exist The wind turbine TLIC frequency control is activated at all times to achieve the correspondence between the maximum frequency response point under TLIC wind power excitation and the minimum frequency response point under load surge.

[0041] This invention provides a wind turbine primary frequency regulation system based on the peak and minimum points of the power grid frequency response, the system comprising:

[0042] The first module is used to detect frequency events, namely, the occurrence of load surges or generator tripping events, and record the occurrence time t0;

[0043] The second module is used to estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation. Based on the correspondence between the maximum frequency response time under TLIC wind power excitation and the minimum frequency response time under sudden load power excitation, the delayed start-up time of the wind turbine using the TLIC method is calculated.

[0044] The third module is used in At any given time, initiate the TLIC method to set the electromagnetic power command for the wind turbine;

[0045] The fourth module is used to restore the fan speed to the initial optimal speed by reducing the electromagnetic power after the fan has reached a stable equilibrium point.

[0046] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it performs the following steps:

[0047] Step 1: Detect frequency events and record the occurrence time t0;

[0048] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0049] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0050] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0051] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0052] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the following steps:

[0053] Step 1: Detect frequency events and record the occurrence time t0;

[0054] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0055] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0056] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0057] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0058] Compared with the prior art, the significant advantages of this invention are:

[0059] 1) Compared with the TLIC method, the newly proposed wind turbine primary frequency regulation control method based on the time of the extreme point overcomes the problem that the maximum value of the frequency response under wind power excitation is always earlier than the minimum value of the frequency corresponding to the frequency power of the sudden load.

[0060] 2) By delaying the start of the wind turbine frequency regulation control, the minimum point of the grid frequency is further increased without affecting the dynamic speed of the wind turbine, thus improving the wind power frequency regulation effect.

[0061] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0062] Figure 1 This is a flowchart of the primary frequency regulation control of the wind turbine based on the maximum and minimum points of the power grid frequency response, according to the present invention.

[0063] Figure 2 This is a schematic diagram of the limited torque inertial control of a wind turbine in one embodiment.

[0064] Figure 3 This is a schematic diagram of the TLIC wind power output and its approximate value in one embodiment.

[0065] Figure 4 This is a schematic diagram showing the time of maximum frequency response under different approximate wind power excitation in one embodiment.

[0066] Figure 5 This is a schematic diagram of the power grid frequency response components under two power excitations in one embodiment.

[0067] Figure 6 This is a schematic diagram of an improved approach based on the times of maximum / minimum frequency response in one embodiment.

[0068] Figure 7 This is a block diagram of the TLIC control principle based on the extreme point of the power grid frequency response in one embodiment.

[0069] Figure 8 The figure shows the frequency regulation effect of the wind turbine under three methods in one embodiment: no frequency regulation, no delay TLIC, and TLIC considering the extreme point. Figures (a) to (d) show the grid frequency, wind turbine output, synchronous unit output, and wind turbine speed, respectively. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0071] It should be noted that if the embodiments of the present invention involve descriptions such as "first" and "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0072] In one embodiment, combined Figure 1 A method for primary frequency regulation control of wind turbines based on the maximum and minimum points of the power grid frequency response is provided. The method includes the following steps:

[0073] Step 1: Detect the power grid frequency deviation. If it exceeds the preset threshold |Δf| thd If the event occurs, it is considered that a sudden load increase or generator tripping event has occurred in the power grid, i.e., a frequency event, and the occurrence time t0 is recorded.

[0074] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0075] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0076] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0077] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0078] Furthermore, in one embodiment, step 2 involves calculating the minimum point of the grid frequency response under step load power excitation. The specific process includes:

[0079] For a load surge event, the grid frequency response Δf under step load power excitation L for:

[0080] Δf L (t)=ΔP L h step (t)

[0081]

[0082]

[0083] In the formula, ΔP L H is the load step disturbance amplitude, D is the system inertia time constant, R is the governor droop coefficient, T is the governor time constant, F is the proportion of high-pressure turbine power to total turbine power, and K is the mechanical power gain coefficient.

[0084] The time of minimum point of the grid frequency response under step load power excitation is:

[0085]

[0086] As can be seen from the above equation, the extreme point of the power grid frequency response under step power excitation is fixed and depends only on the system parameters (H, D, R, T, F, K) and the step excitation amplitude ΔP. L Irrelevant.

[0087] Furthermore, in one embodiment, combined with Figure 2 and Figure 3Step 3, which involves obtaining the relationship between the time of the maximum value of the grid frequency response under TLIC wind power excitation and the time of the minimum value of the grid frequency response under step load power excitation, specifically includes:

[0088] Simplified approximate grid frequency response Δf under TLIC wind power excitation W As shown in the following equation, it can be represented as the superposition of the frequency responses of a step signal and two ramp signals:

[0089] Δf W (t)=ΔP W0 h step (t)u(t)+K P-t h ramp (t)u(t)-K P-t h ramp (t-t1)u(t-t1)

[0090] In the formula, ΔP W0 For the initial support power increment of the wind turbine TLIC method, ΔP W0 =P Tlim (ω0)-P W0 P Tlim (ω0) represents the power of the maximum torque at the initial speed ω0, P W0 K represents the initial electromagnetic power of the wind turbine. P-t t is the slope of the piecewise curve, i.e., the rate of change of wind power; t1 is the time it takes for the simplified wind power to decrease to the electromagnetic power at the equilibrium point; u(t) is the unit step signal, h step (t) represents the unit step response, h ramp (t) represents the unit slope response;

[0091] Differentiating the above equation, we obtain the simplified frequency response rate corresponding to TLIC wind power:

[0092]

[0093] By analyzing Δf' W (t) in The symbols at each point indicate the time of the maximum value of the power grid frequency response. The time of minimum frequency response of the power grid The relationship between the two is based on t1 and The relationship can be divided into the following two cases:

[0094] (1) When Sometimes,

[0095]

[0096] because and KP-t <0, therefore

[0097] (2) When Sometimes,

[0098]

[0099] Because h step (t) in It is increasing, and at the same time so

[0100] therefore, This holds true under TLIC wind power excitation with arbitrary parameters, Δf W (t) in If there exists at least one maximum point within the range, and the first maximum point is also the maximum point, then:

[0101]

[0102] In summary, under the segmented wind power excitation, This holds true regardless of specific parameter settings. The maximum point of the grid frequency response under TLIC wind power excitation always occurs earlier than the minimum point of the frequency corresponding to the step load. This causes the optimal compensation effect of the TLIC method in improving the minimum frequency to occur earlier, thus affecting the frequency regulation effect of the wind turbine TLIC method.

[0103] Furthermore, in one embodiment, due to the minimum point of the grid frequency response under step load power excitation... It is fixed, and the estimated start-up delay time for the TLIC method of starting the wind turbine will be used. The process shifts to estimating the time of the maximum grid frequency response under TLIC wind power excitation, i.e., estimating... Step 4 specifically includes:

[0104] Step 4-1: Based on the simplified TLIC wind power output, the Newton-Raphson method is used to numerically solve for the result. Estimated value;

[0105] Step 4-2: Calculate the delayed start-up time of the wind turbine using the TLIC method.

[0106]

[0107] Furthermore, in one embodiment, step 5 specifically includes: based on the estimated delay start time... exist The wind turbine TLIC frequency regulation control is activated at all times to achieve the correspondence between the maximum frequency response point under TLIC wind power excitation and the minimum frequency point under load surge, so as to compensate for the lowest grid frequency point caused by load surge to the greatest extent.

[0108] In one embodiment, a wind turbine primary frequency regulation system based on the maximum / minimum point of the grid frequency response is provided, the system comprising:

[0109] The first module is used to detect frequency events, namely, the occurrence of load surges or generator tripping events, and record the occurrence time t0;

[0110] The second module is used to estimate the time of the maximum point of the grid frequency response under simplified TLIC wind power excitation. Based on the correspondence between the maximum frequency response time under TLIC wind power excitation and the minimum frequency response time under sudden load power excitation, the delayed start-up time of the wind turbine using the TLIC method is calculated.

[0111] The third module is used in At any given time, initiate the TLIC method to set the electromagnetic power command for the wind turbine;

[0112] The fourth module is used to restore the fan speed to the initial optimal speed by reducing the electromagnetic power after the fan has reached a stable equilibrium point.

[0113] Specific limitations regarding the wind turbine primary frequency regulation system based on the peak value of the grid frequency response can be found in the limitations of the wind turbine primary frequency regulation method based on the peak value moment mentioned above, and will not be repeated here. Each module in the aforementioned wind turbine primary frequency regulation system based on the peak value moment can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0114] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to perform the following steps:

[0115] Step 1: Detect frequency events and record the occurrence time t0;

[0116] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0117] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0118] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0119] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0120] For specific limitations on each step, please refer to the limitations on the wind turbine primary frequency regulation method based on the extreme point of the grid frequency response mentioned above, which will not be repeated here.

[0121] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0122] Step 1: Detect frequency events and record the occurrence time t0;

[0123] Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation.

[0124] Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation.

[0125] Step 4: Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response.

[0126] Step 5, based on the delayed start time Achieve primary frequency regulation control of the fan based on the time of the extreme point.

[0127] For specific limitations on each step, please refer to the limitations on the wind turbine primary frequency regulation method based on the extreme point of the grid frequency response mentioned above, which will not be repeated here.

[0128] As a specific example, the invention will be further verified and illustrated in one embodiment.

[0129] This embodiment utilizes the open-source professional wind turbine simulation software FAST (Fatigue, Aerodynamics, Structures, and Turbulence) provided by the National Renewable Energy Laboratory (NREL) to simulate and verify the effects. The wind power system dynamic model experimental platform mainly consists of three parts: a wind turbine simulator, a synchronous machine simulator, and a regenerative load. The main parameters of the experimental platform are shown in Table 1 below.

[0130] Table 1 Main parameters of the dynamic model experimental platform

[0131]

[0132] The wind turbine primary frequency regulation control method based on the extreme point moment of this invention includes the following:

[0133] 1. Detect whether a frequency event has occurred and record the time of occurrence t0;

[0134] 2. Calculate the time of minimum frequency response of the power grid under step load power excitation. Specifically, it includes:

[0135] For a load surge event, the grid frequency response Δf under step load power excitation L for:

[0136] Δf L (t)=ΔP L h step (t)

[0137]

[0138]

[0139] In the formula, ΔP L Let H be the amplitude of the load step disturbance, D be the system inertia time constant, R be the load damping coefficient, T be the governor droop coefficient, F be the proportion of high-pressure turbine power to total turbine power, and K be the mechanical power gain coefficient. The minimum point of the grid frequency response under step load power excitation is...

[0140]

[0141] 3. Analyze the relationship between the time of the maximum value of the grid frequency response under TLIC wind power excitation and the time of the minimum value of the grid frequency response under step load power excitation, specifically including:

[0142] The actual TLIC wind power is used Figure 3 The dashed line represents the approximate TLIC wind power substitution. The grid frequency response Δf under approximate (simplified) TLIC wind power excitation. W As shown below,

[0143] Δf W (t)=ΔP W0 h step (t)u(t)+K P-t h ramp (t)u(t)-K P-t h ramp (t-t1)u(t-t1)

[0144] In the formula, ΔP W0 For the initial support power increment of the wind turbine TLIC method, ΔP W0 =P Tlim (ω0)-P W0 ;K P-t t1 is the slope of the piecewise curve, which is also the rate of change of wind power; t1 is the time it takes for the simplified wind power to decrease to the electromagnetic power at the equilibrium point C.

[0145] because This holds true under simplified TLIC wind power excitation with arbitrary parameter settings. Therefore, as... Figure 4 and Figure 5 As shown, under arbitrary parameter settings, the maximum value of the grid frequency response under TLIC wind power excitation always occurs earlier than the minimum value of the frequency corresponding to the step load, i.e.

[0146]

[0147] 4. Estimate the time of maximum grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the principle of corresponding extreme point moments. Specifically, it includes:

[0148] Based on approximate TLIC wind power... The estimated values ​​were obtained numerically using the Newton-Raphson method. And The initial value is set to 0. Based on Figure 6 The principle corresponding to the extreme points of the power grid frequency response shown can be used to obtain... and The quantitative relationship is Based on the relationship, the delay time for starting the TLIC method can be estimated.

[0149] 5. Implement primary frequency regulation control of the wind turbine based on the maximum and minimum points of the grid frequency response, according to the delayed start-up time. Specifically, this includes:

[0150] Based on the estimated startup delay, The wind turbine TLIC frequency regulation control is activated continuously to achieve a correspondence between the maximum frequency response point under TLIC wind power excitation and the minimum frequency response point under load surge, thereby maximizing compensation for the grid frequency minimum point caused by load surge. A complete block diagram of the wind turbine primary frequency regulation method based on the grid frequency response maximum / minimum point is shown below. Figure 7 As shown, it includes a frequency event monitoring module, a delay time estimation module, a TLIC frequency support module, a wind turbine speed recovery module, and an MPPT module.

[0151] 6. In an experimental scenario with a constant wind speed of 10 m / s, a wind power penetration rate of approximately 60%, and a load surge event (load surge of 1.5 kW) occurring at 300 s for the regenerative load, the grid frequency, turbine output power, and rotor speed are calculated for three methods: without frequency regulation, without delay, and with delay support in the TLIC. Figure 8 As shown.

[0152] Table 2 Comparison of Frequency Modulation Performance Indicators

[0153]

[0154] Through analysis Figure 8 (a) and the frequency regulation performance indicators in Table 2 show that, based on the TLIC method, by delaying the start-up of wind turbine frequency regulation control, the maximum frequency response point under TLIC wind power excitation and the minimum frequency response point under load surge were correlated, raising the minimum grid frequency from -0.5658Hz to -0.4959Hz. The maximum rate of frequency change in the initial stage after a frequency event is the same as under the MPPT method. From Figure 8 As can be seen from the wind turbine electromagnetic power and rotor speed in (b) and (d), delaying the start-up of the wind turbine's TLIC frequency control does not affect the wind turbine's electromagnetic power and speed dynamics; it merely postpones them. It can be seen that the method proposed in this invention can further improve the minimum grid frequency without affecting the wind turbine's speed dynamics.

[0155] The simulation results above show that the wind turbine primary frequency regulation control method based on the peak and minimum points of the grid frequency response proposed in this invention can achieve the correspondence between the maximum point of the frequency response under TLIC wind power excitation and the minimum point under load surge, further improving the minimum point of the grid frequency and improving the wind power frequency regulation effect.

[0156] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for primary frequency regulation of wind turbines based on the extreme point of the power grid frequency response, characterized in that, The method includes the following steps: Step 1: Detect frequency events and record the time of occurrence. ; Step 2: Calculate the time of minimum frequency response of the power grid under step load power excitation. ; Step 3: Obtain the relationship between the time of the maximum value of the grid frequency response under the TLIC wind power excitation and the time of the minimum value of the grid frequency response under the step load power excitation. Step 4: Estimate the time of the maximum value of the grid frequency response under TLIC wind power excitation. The delayed start-up time of the wind turbine using the TLIC method is calculated based on the correspondence between the extreme points of the power grid frequency response. ; Step 5, based on the delayed start time To achieve primary frequency regulation control of the fan based on the time of the extreme point; Step 3, which involves obtaining the relationship between the time of the maximum value of the grid frequency response under TLIC wind power excitation and the time of the minimum value of the grid frequency response under step load power excitation, specifically includes: Simplified approximate grid frequency response under TLIC wind power excitation As shown in the following equation, it can be represented as the superposition of the frequency responses of a step signal and two ramp signals: In the formula, This represents the initial support power increment for the wind turbine's TLIC method. , Initial rotational speed The power corresponding to the maximum torque at that point. This represents the initial electromagnetic power of the wind turbine. The slope of the piecewise curve is the rate of change of wind power. To simplify the time it takes for wind power to decrease to the electromagnetic power at the equilibrium point; For unit step signal, For unit step response, Unit slope response; Differentiating the above equation, we obtain the simplified frequency response rate corresponding to TLIC wind power: Through analysis exist The symbols at the point indicate the time of the maximum value of the power grid frequency response. The time of minimum frequency response of the power grid The relationship between the two is based on and The relationship can be divided into the following two cases: (1) When Sometimes, because , as well as ,so ; (2) When Sometimes, because exist It is increasing, and at the same time ,so ; therefore, This holds true under TLIC wind power excitation with arbitrary parameters. exist If there exists at least one maximum point within the range, and the first maximum point is also the maximum point, then: 。 2. The wind turbine primary frequency regulation method based on the peak value of the power grid frequency response as described in claim 1, characterized in that, Step 1 specifically involves detecting the power grid frequency deviation; if it exceeds a preset threshold... If this occurs, it is considered that a load surge or generator tripping event has occurred in the power grid, i.e., a frequency event, and the time of occurrence is recorded. .

3. The wind turbine primary frequency regulation method based on the peak value of the power grid frequency response as described in claim 1, characterized in that, Step 2 describes calculating the minimum point of the grid frequency response under step load power excitation. The specific process includes: For load surge events, the grid frequency response under step load power excitation for: In the formula, This represents the amplitude of the load step disturbance. Let be the system's inertial time constant. This is the load damping coefficient. This is the governor droop coefficient. The time constant of the speed controller, This refers to the proportion of high-pressure turbine power to total steam turbine power. This is the mechanical power gain coefficient; The time of minimum point of the grid frequency response under step load power excitation is: : 。 4. The wind turbine primary frequency regulation method based on the peak value of the power grid frequency response as described in claim 3, characterized in that, Step 4 specifically includes: Step 4-1: Based on the simplified TLIC wind power output, the Newton-Raphson method is used to numerically solve for the result. Estimated value; Step 4-2: Calculate the delayed start-up time of the wind turbine using the TLIC method. : 。 5. The wind turbine primary frequency regulation method based on the peak and minimum points of the power grid frequency response as described in claim 4, characterized in that, Step 5 specifically includes: based on the estimated startup delay time ,exist The wind turbine TLIC frequency control is activated at all times to achieve the correspondence between the maximum frequency response point under TLIC wind power excitation and the minimum frequency response point under load surge.

6. A wind turbine primary frequency regulation system based on the time of the maximum and minimum points of the power grid frequency response, according to any one of claims 1 to 5, characterized in that, The system includes: The first module is used to detect frequency events, namely, sudden load increases or generator tripping events, and record the time of occurrence. ; The second module is used to estimate the time of the maximum point of the grid frequency response under simplified TLIC wind power excitation. Based on the correspondence between the maximum frequency response point under TLIC wind power excitation and the minimum frequency response point under sudden load power excitation, the delayed start-up time of the wind turbine using the TLIC method is calculated. ; The third module is used in At any given time, initiate the TLIC method to set the electromagnetic power command for the wind turbine; The fourth module is used to restore the fan speed to the initial optimal speed by reducing the electromagnetic power after the fan has reached a stable equilibrium point.

7. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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