Dynamic assessment method and system for power generation capacity of wind power plant

Abstract

The invention discloses a dynamic assessment method and system for the power generation capacity of a wind power plant, and the method comprises the steps: predicting the wind speed at a next moment according to historical data; calculating the MPPT power at the current moment, and comparing the MPPT power with the actual power at the current moment to calculate the load reduction rate; mPPT power of the fan unit at the next moment is calculated according to the predicted wind speed, and predicted power at the next moment is calculated by multiplying the MPPT power with the load reduction rate; the maximum mechanical power at the next moment is calculated according to the predicted wind speed, and the rotating speed predicted value and the pitch angle predicted value at the next moment are calculated by comparing the maximum mechanical power with the predicted power at the next moment; solving a single-machine adjustment process differential equation of the wind turbine generator set, obtaining tentative generation increasing power, and solving an active adjustable upper limit and a lower limit of the wind turbine generator set according to the tentative generation increasing power; according to the size of the terminal voltage of the fan unit, calculating a reactive adjustable upper limit and a reactive adjustable lower limit of the fan unit; calculating active power generation capacity of the wind power plant; and calculating the reactive power correction coefficient of the wind power plant, and calculating the reactive power generation capacity of the wind power plant according to the reactive power correction coefficient.

Description

Technical Field

[0001] The present invention relates to the field of dynamic evaluation of renewable energy power generation capacity, and in particular to a method and system for dynamic evaluation of wind farm power generation capacity. Background Art

[0002] In the power system, wind farms are an important form of renewable energy generation. Their output is affected by weather conditions, equipment performance and other factors, showing significant intermittency and volatility. In the process of power dispatching, automatic generation control (AGC) and automatic voltage control (AVC) have become key means to maintain the stable operation of the system. However, due to the output characteristics of wind power, its AGC / AVC regulation capacity is not unlimited, but has certain limits. The output limit of the wind farm is restricted by its physical characteristics. For example, the output of the wind turbine is limited by factors such as wind speed, rotor diameter and generator efficiency. These physical characteristics determine the maximum and minimum output limits of the wind farm, limiting its output regulation range during the AGC / AVC regulation process. The safe and stable operation of the power system also puts forward requirements for the AGC / AVC regulation limit of the wind farm. During the operation of the power system, a certain frequency and voltage stability margin needs to be maintained to ensure the normal operation of the system. Therefore, when designing the AGC / AVC regulation strategy of the wind farm, the safety constraints and stability requirements of the system must be considered to avoid excessive regulation leading to system instability. With the large-scale grid-connected operation of renewable energy, the output fluctuation of wind farms has an increasingly significant impact on the power system. In order to cope with this fluctuation, it is necessary to formulate reasonable AGC / AVC adjustment limits to balance the access of renewable energy and the stable operation of the power system. Summary of the invention

[0003] Purpose of the invention: The present invention aims to provide a method for dynamically evaluating the power generation capacity of a wind farm, which can evaluate the upper and lower limits of the active power generation capacity and reactive power generation capacity of the wind farm to ensure the stability and reliability of the AGC / AVC regulation process of the power grid; another purpose of the present invention is to provide a system for dynamically evaluating the power generation capacity of a wind farm.

[0004] Technical solution: The method for dynamically evaluating the power generation capacity of a wind farm according to the present invention comprises the following steps:

[0005] (1) Obtain the historical sampling data v(t-0)~v(t-f+1) of the wind turbine generator set in the wind farm f minutes before the current time t;

[0006] (2) Predict the wind speed v(t+1) at the next moment, and determine the active power of the wind turbine MPPT corresponding to the wind speed at t-0 and t+1 respectively; according to the active power P of the wind turbine in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction rate μ;

[0007] (3) According to the active power P of the wind turbine MPPT at time t+1 MPPT(t+1) and the load reduction rate μ in step (2), calculate the predicted active power value at time t+1; if P (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, calculate the pitch angle β at time t+1 (t+1) If P (t+1) Greater than P m(t+1) , then the pitch angle β at time t+1 (t+1) =0, calculate the fan speed ω at time t+1 (t+1) ;

[0008] (4) Repeat steps (2) to (3) to obtain the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of the wind turbine MPPT from time t+1 to time t+g in the future;

[0009] (5) Based on the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of wind turbine MPPT from time t+1 to time t+g obtained in step (4), a single-machine regulation model of wind turbine is constructed, and the state variable Ω(t=T end )=Ω set The trial additional power P over and the current wind turbine active power regulation capability P up And active power reduction capability P down ;

[0010] (6) According to the current terminal voltage U of the wind turbine generator set, determine the reactive power regulation capacity Q of the wind turbine generator set up and reactive power reduction capability Q down ;

[0011] (7) Calculate the station-level active power regulation capability P of the wind farm up , Active power reduction capability P down and reactive power regulation capability correction term ΔQ l ; According to the voltage U of the wind farm grid connection point pcc , determine the wind farm's station-level reactive power regulation capacity Q up and reactive power reduction capability Q down .

[0012] Furthermore, taking f = 30, the wind speed v(t+1) at the next moment is

[0013] v(t+1)=a0×1.0+a1×v(t-0)+a2×v(t-1)+L+a 30 ×v(t-29) (1)

[0014] Among them, a0~a 30 is the coefficient.

[0015] Furthermore, the MPPT active power, wind turbine speed and pitch angle of the wind turbine generator set under the MPPT state of the wind turbine generator set corresponding to the time t-0 and t+1 are determined as follows:

[0016] If the current wind speed v<4m / s or v>20m / s, then the MPPT fan speed of the fan unit at that moment is ω MPPT =0, active power P MPPT =0, pitch angle β MPPT =90;

[0017] If the current wind speed v>4m / s and v<12m / s, then the MPPT pitch angle β of the wind turbine generator set at this moment MPPT =0, fan speed ω MPPT and active power P MPPT When the pitch angle β = 0 and the wind turbine speed ω is in the interval [0.7, 1.25], the mechanical power P m is the maximum fan speed ω and mechanical power P m Maximum value;

[0018]

[0019] Among them, c1~c8 are fitting parameter constants; K m is the mechanical power coefficient constant; R is the impeller radius;

[0020] If the current wind speed v>12m / s and v<20m / s, then the wind turbine MPPT fan speed ω MPPT =1.25, active power P MPPT =1.0, pitch angle β MPPT When the fan speed ω = 1.25 and the mechanical power P m =1.0 when the pitch angle β.

[0021] Further, according to the active power P of the wind turbine generator set in the MPPT state at time t-0 MPPT(t-0) And the actual active power P (t-0) , the load reduction rate μ is

[0022]

[0023] Furthermore, the predicted active power value P at time t+1 is (t+1) By P MPPT(t+1) It is obtained by multiplying it by the load reduction rate μ.

[0024] Furthermore, the wind turbine unit regulation model is:

[0025]

[0026] The initial state of the state variable is

[0027]

[0028] Among them, J WTG is the moment of inertia of the fan; T end Support end time; β is a constant, Ω(t) is a state variable, 0≤t≤T end , P m is the mechanical power, P over To test the power increase, β MPPT is the MPPT pitch angle.

[0029] Furthermore, when the power P is tested over In the range 0≤P over ≤1, according to the state variable Ω(t=T end )=Ω set The trial additional power P over , calculate the active power regulation capacity P of the wind turbine generator set up and active power reduction capability P down ;

[0030]

[0031] Where S is the rated capacity of the computing unit; Ω set is the set minimum speed of the wind turbine, P is the current active power of the wind turbine, and Q is the current reactive power of the wind turbine.

[0032] Furthermore, according to the current terminal voltage U of the wind turbine generator set, the reactive power regulation capacity Q of the wind turbine generator set is determined. up and reactive power reduction capability Q down The details are as follows:

[0033] If the current terminal voltage of a single wind turbine generator set is U≥0 and U<0.9, the reactive power regulation capacity of a single wind turbine generator set is Q up and reactive power reduction capability Q down for

[0034]

[0035] Among them, K1 is the coefficient;

[0036] If the current terminal voltage of a single wind turbine generator set is U≥0.9 and U≤1.3, the reactive power regulation capacity of a single wind turbine generator set is Q upand reactive power reduction capability Q down for

[0037]

[0038] Among them, P is the current active power of the wind turbine, and S is the rated capacity of the calculation unit.

[0039] Furthermore, the wind farm’s station-level active power regulation capability P up and active power reduction capability P down for

[0040]

[0041] Among them, P WTGup and P WTGdown They represent the active power regulation capability P of each wind turbine in the wind farm. up and active power reduction capability P down ;

[0042] Reactive power regulation capability correction term ΔQ l for

[0043]

[0044] Among them, P is the active power of each wind turbine in the wind farm, Q is the reactive power of each wind turbine in the wind farm, and X eq is the coefficient, U PCC is the voltage at the wind farm grid connection point;

[0045] If the voltage at the wind farm connection point is U pcc ≥0 and U pcc <0.9, the wind farm’s station-level reactive power regulation capacity Q up and reactive power reduction capability Q down for

[0046]

[0047] Among them, K1 is the coefficient, U WTG is the terminal voltage of each fan unit;

[0048] If the voltage at the wind farm connection point is U pcc ≥0.9 and U pcc ≤1.3, the wind farm’s station-level reactive power regulation capacity Q up and reactive power reduction capability Q down for

[0049]

[0050] Among them, P WTG is the active power of each fan unit, U WTG is the terminal voltage of each fan unit, SWTG It is the ratio of the actual rated capacity of each fan unit to the actual rated power.

[0051] The wind farm power generation capacity dynamic evaluation system of the present invention comprises:

[0052] The data sampling module is used to obtain the historical sampling data v(t-0)~v(t-f+1) of the wind turbine generator set in the wind farm f minutes before the current time t;

[0053] The calculation module is used to predict the wind speed v(t+1) at the next moment, and determine the active power of the wind turbine MPPT corresponding to the wind speed at t-0 and t+1 respectively; according to the active power P of the wind turbine in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction rate μ; according to the active power P of the wind turbine MPPT at time t+1 MPPT(t+1) and the load reduction rate μ, calculate the predicted active power value at time t+1; if P (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, calculate the pitch angle β at time t+1 (t+1) If P (t+1) Greater than P m(t+1) , then the pitch angle β at time t+1 (t+1) =0, calculate the fan speed ω at time t+1 (t+1) ; Obtain the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of wind turbine MPPT from time t+1 to t+g in the future;

[0054] A model building module is used to build a single-machine regulation model of a wind turbine generator set according to the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of the wind turbine generator set MPPT at the future time t+1 to t+g;

[0055] Dynamic capability solving module, used to solve the state variable Ω(t=T end )=Ω set The trial additional power P over and the current wind turbine active power regulation capability P up And active power reduction capability P down ; According to the current terminal voltage U of the wind turbine generator set, determine the reactive power increase capacity Q of the wind turbine generator set up and reactive power reduction capability Q down ; Calculate the station-level active power regulation capability P of the wind farm up , Active power reduction capability P down and reactive power regulation capability correction term ΔQ l ; According to the voltage U of the wind farm grid connection pointpcc , determine the wind farm's station-level reactive power regulation capacity Q up and reactive power reduction capability Q down .

[0056] Beneficial effect: Compared with the prior art, the significant advantage of the present invention is that the present invention uses the historical data of the 30 minutes before the current moment to rollingly predict the wind speed, pitch angle, rotation speed and active power of each wind turbine in the next 16 minutes, and based on this, calculates the upper and lower limits of the active power adjustment and the upper and lower limits of the reactive power adjustment of each wind turbine in the next 16 minutes, and finally predicts the site-level power generation capacity of the entire wind farm in the next 16 minutes, further improving the perception ability of the AGC / AVC regulation system and ensuring the rationality and reliability of AGC / AVC regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0058] The present invention will be further described below in conjunction with the accompanying drawings.

[0059] The method for dynamically evaluating the power generation capacity of a wind farm according to the present invention comprises the following steps:

[0060] 1) Obtain the historical sampling data v(t-0)~v(t-29) of the wind turbine unit 30 minutes before the current moment, and predict the wind speed v(t+1) at the next moment.

[0061] 2) Calculate the MPPT state of the wind turbine corresponding to the wind speed v(t-0) at time t-0, including the MPPT power P MPPT(t-0) ,MPPT speedω MPPT(t-0) , MPPT pitch angle β MPPT(t-0) .

[0062] 3) According to the active power P of the wind turbine in the MPPT state at time t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction factor μ.

[0063] 4) According to the wind speed v(t+1) at time t+1 obtained in 1), calculate the active power P under the MPPT state at time t+1 MPPT(t+1) The active power P under MPPT state at time t+1 MPPT(t+1) Multiply it by the load reduction rate μ in 3) to calculate the predicted active power value P at time t+1 (t+1) .

[0064] 5) Calculate the mechanical power P of the wind turbine at time t+1 when the wind speed ω=1.25, the pitch angle β=0, and the wind speed v(t+1) at time t+1 m(t+1) .

[0065] If the predicted active power value P at time t+1 is (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, active power P (t+1) , wind speed v(t+1), and calculate the pitch angle β at time t+1 (t+1) .

[0066] If the predicted active power value P at time t+1 is (t+1) Greater than the mechanical power P of the fan at time t+1 m(t+1) , then the pitch angle β at time t+1 (t+1) =0, active power P (t+1) , wind speed v(t+1), and calculate the fan speed ω at time t+1 (t+1) .

[0067] 6) Take the predicted wind speed at time t+1 as the historical wind speed at time t+2, repeat the above steps 1) to 5) to obtain the predicted values ​​of wind speed v, wind turbine speed ω, pitch angle β, and active power P from time t+1 to t+16 in the future, a total of 16 groups.

[0068] 7) Test the additional power P over In the range 0≤P over ≤1, find the solution that makes the state variable Ω(t=T end )=Ω set The trial additional power P over In this state, the fan active power adjustment capacity P up and active power reduction capability P down They are:

[0069]

[0070] Where S is the rated capacity of the computing unit; Ω set is the set minimum speed of the fan, P is the current active power of the fan, and Q is the current reactive power of the fan.

[0071] 8) If the wind turbine terminal voltage U≥0 and U<0.9, then the wind turbine reactive power regulation capacity Q up And reactive power reduction capability Q down They are:

[0072]

[0073] Among them, K1 is the coefficient.

[0074] If the wind turbine terminal voltage U≥0.9 and U≤1.3, then the wind turbine reactive power regulation capacity Q up And reactive power reduction capability Qdown They are:

[0075]

[0076] Among them, P is the current active power of the wind turbine, and S is the rated capacity of the calculation unit.

[0077] 9) Calculate the site-level active power regulation capability P of the wind farm being evaluated up and active power reduction capability P down :

[0078]

[0079] Among them, P WTGup and P WTGdown are the active power regulation capacity P of each wind turbine in the wind farm. up and active power reduction capability P down .

[0080] 10) Calculate the correction term ΔQ of the reactive power regulation capability of the wind farm evaluated l :

[0081]

[0082] Among them, P is the active power of each wind turbine in the wind farm, Q is the reactive power of each wind turbine in the wind farm, and X eq is the coefficient, U PCC is the grid connection point voltage of the wind farm.

[0083] 11) If the wind farm grid connection point voltage U pcc ≥0 and U pcc <0.9, then the wind farm’s station-level reactive power regulation capacity Q up and reactive power reduction capability Q down They are:

[0084]

[0085] Among them, K1 is the coefficient, U WTG is the terminal voltage of each fan unit.

[0086] If the voltage at the wind farm connection point is U pcc ≥0.9 and U pcc ≤1.3, then the wind farm’s station-level reactive power regulation capacity Q up and reactive power reduction capability Q down They are:

[0087]

[0088] Among them, P WTG is the active power of each fan unit, UWTG is the terminal voltage of each fan unit, S WTG It is the ratio of the actual rated capacity of each fan unit to the actual rated power.

[0089] The wind farm power generation capacity dynamic evaluation system of the present invention comprises:

[0090] The data sampling module is used to obtain the historical sampling data v(t-0)~v(t-f+1) of the wind turbine generator set in the wind farm f minutes before the current time t;

[0091] The calculation module is used to predict the wind speed v(t+1) at the next moment, and determine the active power of the wind turbine MPPT corresponding to the wind speed at t-0 and t+1 respectively; according to the active power P of the wind turbine in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction rate μ; according to the active power P of the wind turbine MPPT at time t+1 MPPT(t+1) and the load reduction rate μ, calculate the predicted active power value at time t+1; if P (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, calculate the pitch angle β at time t+1 (t+1) If P (t+1) Greater than P m(t+1) , then the pitch angle β at time t+1 (t+1) =0, calculate the fan speed ω at time t+1 (t+1) ; Obtain the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of wind turbine MPPT from time t+1 to t+g in the future;

[0092] A model building module is used to build a single-machine regulation model of a wind turbine generator set according to the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of the wind turbine generator set MPPT at the future time t+1 to t+g;

[0093] Dynamic capability solving module, used to solve the state variable Ω(t=T end )=Ω set The trial additional power P over and the current wind turbine active power regulation capability P up and active power reduction capability P down ; According to the current terminal voltage U of the wind turbine generator set, determine the reactive power increase capacity Q of the wind turbine generator set up And reactive power reduction capability Q down ; Calculate the station-level active power regulation capability P of the wind farm up , Active power reduction capability P down and reactive power regulation capability correction term ΔQl ; According to the grid connection point voltage Upcc of the wind farm, determine the site-level reactive power regulation capacity Q of the wind farm up And reactive power reduction capability Q down .

[0094] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0095] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

Claims

1. A method for dynamically evaluating the power generation capacity of a wind farm, characterized in that: The following steps are involved: (1) Obtain the historical sampling data v(t-0)~v(t-f+1) of the wind turbine generator set in the wind farm f minutes before the current time t; (2) Predict the wind speed v(t+1) at the next moment and determine the wind turbine generators corresponding to the wind speed at t-0 and t+1 respectively The active power of the wind turbine group MPPT; according to the active power P of the wind turbine group in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction rate μ; (3) According to the active power P of the wind turbine MPPT at time t+1 MPPT(t+1) and the load reduction rate μ in step (2), calculate the predicted active power value at time t+1; if P (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, calculate the pitch angle β at time t+1 (t+1) If P (t+1) Greater than P m(t+1) , then the pitch angle β at time t+1 (t+1) =0, calculate the fan speed ω at time t+1 (t+1) ; (4) Repeat steps (2) to (3) to obtain the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of the wind turbine MPPT from time t+1 to time t+g in the future; (5) Based on the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of wind turbine MPPT from time t+1 to time t+g obtained in step (4), a single-machine regulation model of wind turbine is constructed, and the state variable Ω(t=T end )=Ω set The trial additional power P over and the current wind turbine active power regulation capability P up And active power reduction capability P down ; (6) According to the current terminal voltage U of the wind turbine generator set, determine the reactive power regulation capacity Q of the wind turbine generator set up And reactive power reduction capability Q down ; (7) Calculate the station-level active power regulation capability P of the wind farm up , Active power reduction capability P down and reactive power regulation capability correction term ΔQ l ; According to the voltage U of the wind farm grid connection point pcc , determine the wind farm's station-level reactive power regulation capacity Q up And reactive power reduction capability Q down .

2. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 1, characterized in that: Take f = 30, the wind speed v(t+1) at the next moment is v(t+1)=a0×1.0+a1×v(t-0)+a2×v(t-1)+L+a 30 ×v(t-29) (1) Among them, a0~a 30 is the coefficient.

3. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 2, characterized in that: Determine the MPPT active power, wind turbine speed and pitch angle of the wind turbine under the MPPT state of the wind turbine corresponding to time t-0 and t+1, as follows: If the current wind speed v<4m / s or v>20m / s, then the MPPT fan speed of the fan unit at that moment is ω MPPT =0, active power P MPPT =0, pitch angle β MPPT =90; If the current wind speed v>4m / s and v<12m / s, then the MPPT pitch angle β of the wind turbine generator set at this moment MPPT =0, fan speed ω MPPT and active power P MPPT When the pitch angle β = 0 and the wind turbine speed ω is in the interval [0.7, 1.25], the mechanical power P m is the maximum fan speed ω and mechanical power P m Maximum value; Among them, c1~c8 are fitting parameter constants; K m is the mechanical power coefficient constant; R is the impeller radius; If the current wind speed v>12m / s and v<20m / s, then the wind turbine MPPT fan speed ω MPPT =1.25, active power P MPPT =1.0, pitch angle β MPPT When the fan speed ω = 1.25 and the mechanical power P m =1.0 when the pitch angle β.

4. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 3, characterized in that: According to the active power P of the wind turbine generator set in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) , the load reduction rate μ is 5. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 4, characterized in that: Active power prediction value P at time t+1 (t+1) By P MPPT(t+1) It is obtained by multiplying it by the load reduction rate μ.

6. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 5, characterized in that: The single-machine regulation model of wind turbine generator set is: The initial state of the state variable is Ω(t=0)=ω (5) Among them, J WTG is the moment of inertia of the fan; T end Support end time; β is a constant, Ω(t) is a state variable, 0≤t≤T end , P m is the mechanical power, P over To test the power increase, β MPPT is the MPPT pitch angle.

7. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 6, characterized in that: When the test power P over In the range 0≤P over ≤1, according to the state variable Ω(t=T end )=Ω set The trial additional power P over , calculate the active power regulation capacity P of the wind turbine generator set up and active power reduction capability P down ; Among them, S is the rated capacity of the calculation unit, Ω set is the minimum speed of the wind turbine, P is the current active power of the wind turbine, and Q is the current reactive power of the wind turbine.

8. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 7, characterized in that: According to the current terminal voltage U of the wind turbine generator set, determine the reactive power regulation capacity Q of the wind turbine generator set. up And reactive power reduction capability Q down The details are as follows: If the current terminal voltage of a single wind turbine generator set is U≥0 and U<0.9, the reactive power regulation capacity of a single wind turbine generator set is Q up And reactive power reduction capability Q down for Among them, K1 is the coefficient; If the current terminal voltage of a single wind turbine generator set is U≥0.9 and U≤1.3, the reactive power regulation capacity of a single wind turbine generator set is Q up And reactive power reduction capability Q down for Among them, P is the current active power of the wind turbine, and S is the rated capacity of the calculation unit.

9. The method for dynamically evaluating the power generation capacity of a wind farm according to claim 8, characterized in that: The station-level active power regulation capability of wind farms P up and active power reduction capability P down for Among them, P WTGup and P WTGdown They represent the active power regulation capability P of each wind turbine in the wind farm. up and active power reduction capability P down ; Reactive power regulation capability correction term ΔQ l for Among them, P is the active power of each wind turbine in the wind farm, Q is the reactive power of each wind turbine in the wind farm, and X eq is the coefficient, U PCC is the voltage at the wind farm grid connection point; If the voltage at the wind farm connection point is U pcc ≥0 and U pcc <0.9, the wind farm’s station-level reactive power regulation capacity Q up And reactive power reduction capability Q down for Among them, K1 is the coefficient, U WTG is the terminal voltage of each fan unit; If the voltage at the wind farm connection point is U pcc ≥0.9 and U pcc ≤1.3, the wind farm’s station-level reactive power regulation capacity Q up And reactive power reduction capability Q down for Among them, P WTG is the active power of each fan unit, U WTG is the terminal voltage of each fan unit, S WTG It is the ratio of the actual rated capacity of each fan unit to the actual rated power.

10. A wind farm power generation capacity dynamic assessment system, characterized in that: include The data sampling module is used to obtain the historical sampling data v(t-0)~v(t-f+1) of the wind turbine generator set in the wind farm f minutes before the current time t; The calculation module is used to predict the wind speed v(t+1) at the next moment, and determine the active power of the wind turbine MPPT corresponding to the wind speed at t-0 and t+1 respectively; according to the active power P of the wind turbine in the MPPT state at t-0 MPPT(t-0) And the actual active power P (t-0) Calculate the load reduction rate μ; According to the active power P of the wind turbine MPPT at time t+1 MPPT(t+1) and the load reduction rate μ, calculate the predicted active power value at time t+1; if P (t+1) Less than or equal to the mechanical power P of the fan at time t+1 m(t+1) , then the fan speed ω at time t+1 (t+1) =1.25, calculate the pitch angle β at time t+1 (t+1) If P (t+1) Greater than P m(t+1) , then the pitch angle β at time t+1 (t+1) =0, calculate the fan speed ω at time t+1 (t+1) ; Obtain the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of wind turbine MPPT from time t+1 to t+g in the future; A model building module is used to build a single-machine regulation model of a wind turbine generator set according to the predicted values ​​of wind speed, wind turbine speed, pitch angle and active power of the wind turbine generator set MPPT at the future time t+1 to t+g; Dynamic capability solving module, used to solve the state variable Ω(t=T end )=Ω set The trial additional power P over and the current wind turbine active power regulation capability P up And active power reduction capability P down ; According to the current terminal voltage U of the wind turbine generator set, determine the reactive power increase capacity Q of the wind turbine generator set up And reactive power reduction capability Q down ; Calculate the station-level active power regulation capability P of the wind farm up , Active power reduction capability P down and reactive power regulation capability correction term ΔQ l ; According to the voltage U of the wind farm grid connection point pcc , determine the wind farm's station-level reactive power regulation capacity Q up And reactive power reduction capability Q down .

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