Wind turbine generator group frequency response method based on laser radar wind measurement

Abstract

The invention relates to the technical field of wind power generation control, in particular to a wind turbine generator group frequency response method based on laser radar wind measurement, which comprises the following steps: acquiring wind speed in front of a wind wheel and unit operation data in real time; calculating a wind turbine generator wheel inlet wind speed time sequence; establishing a wind speed-theoretical available power prediction model of the wind turbine generator; classifying the wind turbine generator sets; dynamically adjusting the operation state of each wind turbine generator participating in frequency response; performing fast frequency response control on the wind turbine generator group according to the frequency change of the power grid; and after the frequency response ends, recovering and keeping the operation state of the wind turbine generator. According to the method, the running state of each wind turbine generator is dynamically adjusted to ensure that each wind turbine generator has sufficient power reserve at the time of frequency response, the output power of each wind turbine generator can be adjusted in a short time, the change of the frequency of the power grid can be quickly responded, the stable running of the power grid is maintained, and the frequency response performance of the wind turbine generator group is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation control, and in particular to a frequency response method of a wind turbine group based on laser radar wind measurement. Background Art

[0002] Wind power generation is one of the most mature and commercially promising power generation methods in the field of renewable energy. The frequency response of a wind turbine refers to the degree of change in the active power output of a wind turbine relative to the frequency deviation when the grid frequency is disturbed beyond the allowable range. Usually, the power grid maintains a stable power frequency to ensure the normal operation of the power system. However, wind energy has the characteristics of randomness, volatility, and low energy density. Due to the influence of weather and other factors, the wind direction and wind speed of wind turbines are constantly changing, which makes it impossible for wind turbines to maintain stable output. Their output power fluctuates, and they are unable to effectively respond to changes in grid frequency and provide reliable frequency modulation functions. When a wind turbine is subject to external disturbances, such as changes in grid frequency or other load changes, the wind turbine needs to adjust its own control system to maintain its output power and frequency stability.

[0003] The existing wind turbine frequency response control methods mainly include reserved active power reserve, additional energy storage system and rotor inertia control. Among them, the reserved active power reserve method reserves output space based on the current theoretical output of the unit, without considering the wind speed changes of each unit in the future, which may easily cause the power support capacity to fail to meet the frequency response; the additional energy storage system method requires a large one-time investment and is limited by the number of energy storage cycles, making it difficult to adapt to high-frequency frequency regulation tasks; the rotor inertia control method only relies on the rotor's own kinetic energy release, has limited power support capacity, and has the problem of secondary frequency drop. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the frequency response performance of the wind turbine generator set cannot be guaranteed.

[0005] In order to solve the above technical problems, the present invention provides a wind turbine group frequency response method based on laser radar wind measurement, comprising:

[0006] S1. Using the laser radar anemometer of the wind turbine to collect radial wind speeds at different distances in front of the wind rotor rotation plane in real time, and establish a wind speed-distance matrix;

[0007] S2. The wind speed-distance matrix is ​​modified according to fluid mechanics, and a discrete sequence of the wind speed at the rotor rotation plane is obtained by extrapolation according to the wind speed-distance matrix. The discrete sequence of the wind speed is fitted by an interpolation fitting algorithm to obtain a continuous time series of the wind speed;

[0008] S3, based on the wind speed-power curve pre-fitted with historical data of the wind turbine, the theoretically generateable power time series of the wind turbine is calculated according to the continuous time series of the wind speed at the turbine inlet, so as to obtain the theoretically generateable power and the average theoretically generateable power of the wind turbine in each time window;

[0009] S4, selecting wind turbines whose average theoretically available power within the time window is greater than or equal to a preset proportion of wind turbine rated power to participate in frequency response;

[0010] S5, adjusting the wind turbine generator set participating in the frequency response to a limited power operation mode, and adjusting the limited power output target value thereof in real time according to the theoretically available power of the wind turbine generator set within the time window;

[0011] S6, collecting the grid frequency of the grid connection point in real time, and when it is monitored that the grid frequency deviation of the grid connection point is greater than the dead zone range, controlling the wind turbines participating in the frequency response to adjust the output power, calculating the output power adjustment amplitude of the wind turbines participating in the frequency response, and calculating the output power of each wind turbine participating in the frequency response according to the current output power and theoretically available power of each wind turbine participating in the frequency response;

[0012] S7. After the frequency response is completed, the grid frequency is restored to the dead zone range, and the wind turbines participating in the frequency response enter the speed recovery mode in an orderly manner, and return to S5 after the speed is restored.

[0013] In one embodiment of the present invention, in S3, the wind speed-power curve is fitted by using the actual measured rotor-entry wind speed and power history data of the wind turbine generator set, and the wind speed-power curve is corrected for air density.

[0014] In one embodiment of the present invention, in S4, wind turbines whose average theoretically available power within the time window is less than a preset proportion of the rated power of the wind turbines or wind turbines in the starting area are selected not to participate in the frequency response and maintain a free power generation state; model wind turbines in a free power generation state or out of service wind turbines are selected not to participate in the frequency response.

[0015] In one embodiment of the present invention, in S4, the preset proportion of the rated power of the wind turbine generator set is 20%, and the value range of the time window is 20 seconds to 30 seconds.

[0016] In one embodiment of the present invention, in S5, adjusting the target power output value of the wind turbine generator set in real time according to the theoretically available power of the wind turbine generator set includes:

[0017] The target power output value P of the i-th wind turbine group si for:

[0018]

[0019] Among them, Pti is the theoretical power that can be generated by the i-th wind turbine in the time window, η is the frequency modulation power change limit ratio, P N is the rated installed capacity of the wind turbine group, is the average theoretical power that can be generated by the i-th wind turbine in the time window, and m is the total number of wind turbines participating in the frequency response.

[0020] In one embodiment of the present invention, in S5, the power limiting operation mode adopts a generator overspeed operation mode, and when the wind turbine is already at the maximum speed, a pitch angle adjustment mode is adopted.

[0021] In one embodiment of the present invention, in S6, the output power adjustment amplitude of the wind turbine generator system participating in the frequency response is:

[0022]

[0023] Among them, K f is the primary frequency modulation active frequency modulation coefficient, f is the grid frequency, T J is the equivalent inertia time constant, t is time, P N is the rated installed capacity of the wind turbine group, f N is the rated frequency of the power grid.

[0024] In one embodiment of the present invention, the primary frequency modulation active frequency modulation coefficient K f The value range is [10,50], and the equivalent inertia time constant T J The value range is [8,12].

[0025] In one embodiment of the present invention, in S6, the step of calculating the output power of each wind turbine generator system participating in the frequency response according to the current output power and the theoretically available power thereof includes:

[0026] The output power of the frequency response of the i-th wind turbine is Where P oi is the current output power of the i-th wind turbine, is the average theoretical power that can be generated by the i-th wind turbine in the time window, m is the total number of wind turbines participating in the frequency response, and ΔP is the output power adjustment amplitude of the wind turbines participating in the frequency response.

[0027] In one embodiment of the present invention, in S7, after the frequency response ends, each wind turbine generator system participating in the frequency response resumes power output in multiple rounds according to its power generation capacity.

[0028] The above technical solution of the present invention has the following advantages compared with the prior art:

[0029] The method for wind turbine group frequency response based on laser radar wind measurement described in the present invention uses a laser radar anemometer installed on the top of the wind turbine nacelle to collect wind speed data in front of the wind turbine rotor plane in real time, predict the wind speed entering the rotor, and further calculate the theoretical power that can be generated by the wind turbine in the next time period. The power output target value of each wind turbine in operation and its output power for frequency response are dynamically adjusted according to the theoretical power that can be generated by each wind turbine, so as to ensure that each wind turbine has sufficient power reserve at the time of frequency response, can adjust its own output power in a short time, quickly respond to changes in the power grid frequency, maintain the stable operation of the power grid, and significantly improve the frequency response performance of the wind turbine group. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0031] Figure 1 It is a flow chart of a wind turbine group frequency response method based on laser radar wind measurement of the present invention;

[0032] Figure 2 It is a schematic diagram of the laser radar anemometer provided in an embodiment of the present invention measuring wind speeds at different distances. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0034] Reference Figure 1 As shown, the present invention provides a wind turbine group frequency response method based on laser radar wind measurement, the steps comprising:

[0035] S1. Reference Figure 2 As shown in the figure, the laser radar anemometer installed above the wind turbine cabin emits a high-frequency laser beam into the atmosphere in front of the wind rotor rotation plane, and collects the radial wind speed corresponding to different distances in front of the wind rotor rotation plane in real time, that is, the wind speed in the axial direction of the wind rotor. Establish the wind speed-distance matrix v 激光 = {v i ,l i |i=1,2,…,n}; where v i , l i Indicates the distance l measured in front of the wind rotor rotation plane i The wind speed at v i .

[0036] The wind turbine operating data collected in real time by the laser radar anemometer also includes the active power, wind turbine speed, etc. of the current wind turbine.

[0037] S2. Considering the influence of factors such as terrain and roughness in the area where the wind turbine is located on the atmospheric flow field, the wind speed-distance matrix v is calculated based on the calculation method of fluid mechanics or micro-meteorology. 激光 Correction is performed and the discrete sequence v of the wind speed at the rotor rotation plane is obtained by extrapolation. 激光,i =f(v i ,l i ,k); where v 激光,i It represents the wind speed at the rotor rotation plane at different time intervals in the future. k is the wind speed correction factor considering factors such as air density, altitude, terrain, roughness, etc., and g is the conversion function.

[0038] The discrete series v of the wind speed at the rotor rotation plane is calculated by interpolation fitting algorithm. 激光,i Fitting is performed to obtain a continuous time series of wind speed entering the rotor.

[0039] S3, based on the wind speed-power curve pre-fitted with historical data of wind turbines, according to the continuous time series of wind speed v t The theoretically generateable power time series of the wind turbine is calculated to obtain the theoretically generateable power and the average theoretically generateable power of the wind turbine in each time window.

[0040] The relationship between the theoretically available power and wind speed is P t =g(v t ).

[0041] The length of the theoretically transmittable power time series is determined by the measurement distance and wind speed conditions of the laser radar anemometer.

[0042] The wind speed-power curve is obtained by fitting the actual measured wind speed at the rotor and the historical power data of the wind turbine and correcting it by air density.

[0043] S4, according to the inlet wind speed v in the inlet wind speed time series t , wind speed at rotor v t The corresponding theoretical power P t In the time window t a According to the changes in the time window t, the wind turbines are divided into three categories: a The wind turbines whose average theoretically available power is greater than or equal to the preset proportion of wind turbine rated power participate in the frequency response; a Wind turbines whose internal average theoretically available power is less than a preset proportion of the rated power of wind turbines or wind turbines in the starting area do not participate in the frequency response and remain in a free power generation state; model wind turbines in a free power generation state or out of service wind turbines are selected not to participate in the frequency response.

[0044] Preferably, the preset proportion of the rated power of the wind turbine generator set is 20%.

[0045] Preferably, according to the actual situation of the frequency variation characteristics of the power system, the value range of the time window is 20 seconds to 30 seconds.

[0046] S5. According to the reserved output ratio required to maintain the frequency regulation capability of the wind turbine group, the wind turbines participating in the frequency response are adjusted to the limited power operation mode, and the limited power output target value is adjusted in real time according to the theoretically available power of the wind turbines within the time window.

[0047] The target power output value P of the i-th wind turbine group si for:

[0048]

[0049] Among them, P ti is the theoretical power that can be generated by the i-th wind turbine in the time window, η is the frequency modulation power change limit ratio, P N is the rated installed capacity of the wind turbine group, is the average theoretical power that can be generated by the i-th wind turbine in the time window, and m is the total number of wind turbines participating in the frequency response.

[0050] Preferably, the power-limited operation mode adopts a generator overspeed operation mode, and when the wind turbine is already at the maximum speed, a pitch angle is adjusted.

[0051] S6. Collect the grid frequency f of the grid connection point in real time and adjust the output power of the wind turbine group according to the frequency change: when it is monitored that the grid frequency deviation of the grid connection point is greater than the dead zone range, control the wind turbines participating in the frequency response to adjust the output power.

[0052] The output power adjustment amplitude of the wind turbine generator system participating in the frequency response is:

[0053]

[0054] Among them, K f is the primary frequency modulation active frequency modulation coefficient, f is the grid frequency, T J is the equivalent inertia time constant, t is time, P N is the rated installed capacity of the wind turbine group, f N is the rated frequency of the power grid.

[0055] Preferably, according to the actual situation of the power system, the primary frequency modulation active frequency modulation coefficient K f The value range is [10,50], and the equivalent inertia time constant T J The value range is [8,12].

[0056] The output power of the frequency response of the i-th wind turbine is:

[0057]

[0058] Where P oi is the current output power of the i-th wind turbine, is the average theoretical power that can be generated by the i-th wind turbine in the time window, m is the total number of wind turbines participating in the frequency response, and ΔP is the output power adjustment amplitude of the wind turbines participating in the frequency response.

[0059] S7. After the frequency response is completed, the grid frequency is restored to the dead zone range, and the wind turbines participating in the frequency response enter the speed recovery mode in an orderly manner, and return to S5 after the speed is restored.

[0060] Preferably, after the frequency response ends, each wind turbine generator system participating in the frequency response resumes power output in multiple rounds according to its power generation capacity, so as to prevent the wind turbine generator systems from resuming rotation speed at the same time, causing a secondary drop in system frequency.

[0061] The method for frequency response of a wind turbine group based on laser radar wind measurement described in the present invention uses a laser radar anemometer installed on the top of the wind turbine nacelle to collect wind speed data in front of the wind turbine rotor plane in real time, predict the wind speed entering the rotor, and further calculate the theoretical power that can be generated by the wind turbine in the next time period. The power output target value of each wind turbine in operation and the output power of the frequency response are dynamically adjusted according to the theoretical power that can be generated by each wind turbine, so as to ensure that each wind turbine has sufficient power reserve at the time of frequency response, can adjust its own output power in a short time, quickly respond to changes in the grid frequency, maintain the stable operation of the grid, and significantly improve the frequency response performance of the wind turbine group. The present invention solves the problem that the power support capacity of the wind turbine is unreliable and the frequency response performance cannot be guaranteed due to the lag of the wind speed behind the wind rotor in the traditional method.

[0062] The method of the present invention is particularly suitable for situations where wind conditions vary greatly in complex terrain and the wake influence of unit arrangement is large, and it does not rely on additional energy storage systems and is easy to promote and apply.

[0063] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A wind turbine group frequency response method based on laser radar wind measurement, characterized in that: include: S1. Using the laser radar anemometer of the wind turbine to collect radial wind speeds at different distances in front of the wind rotor rotation plane in real time, and establish a wind speed-distance matrix; S2. The wind speed-distance matrix is ​​modified according to fluid mechanics, and a discrete sequence of the wind speed at the rotor rotation plane is obtained by extrapolation according to the wind speed-distance matrix. The discrete sequence of the wind speed is fitted by an interpolation fitting algorithm to obtain a continuous time series of the wind speed; S3, based on the wind speed-power curve pre-fitted with historical data of the wind turbine, the theoretically generateable power time series of the wind turbine is calculated according to the continuous time series of the wind speed at the turbine inlet, so as to obtain the theoretically generateable power and the average theoretically generateable power of the wind turbine in each time window; S4, selecting wind turbines whose average theoretically available power within the time window is greater than or equal to a preset proportion of wind turbine rated power to participate in frequency response; S5, adjusting the wind turbine generator set participating in the frequency response to a limited power operation mode, and adjusting the limited power output target value thereof in real time according to the theoretically available power of the wind turbine generator set within the time window; S6, collecting the grid frequency of the grid connection point in real time, and when it is monitored that the grid frequency deviation of the grid connection point is greater than the dead zone range, controlling the wind turbines participating in the frequency response to adjust the output power, calculating the output power adjustment amplitude of the wind turbines participating in the frequency response, and calculating the output power of each wind turbine participating in the frequency response according to the current output power and theoretically available power of each wind turbine participating in the frequency response; S7. After the frequency response is completed, the grid frequency is restored to the dead zone range, and the wind turbines participating in the frequency response enter the speed recovery mode in an orderly manner, and return to S5 after the speed is restored.

2. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1 is characterized in that: In S3, the wind speed-power curve is fitted by using the actual measured rotor-entry wind speed and power history data of the wind turbine generator set, and the wind speed-power curve is corrected for air density.

3. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1 is characterized in that: In S4, wind turbines whose average theoretically available power within the time window is less than a preset proportion of the rated power of the wind turbines or wind turbines in the starting area are selected not to participate in the frequency response and maintain a free power generation state; model wind turbines in a free power generation state or out of service wind turbines are selected not to participate in the frequency response.

4. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1 is characterized in that: In S4, the preset proportion of the rated power of the wind turbine generator set is 20%, and the value range of the time window is 20 seconds to 30 seconds.

5. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1, characterized in that: In S5, adjusting the target power output value of the wind turbine generator set in real time according to the theoretically available power of the wind turbine generator set includes: The target power output value P of the i-th wind turbine group si for: Among them, P ti is the theoretical power that can be generated by the i-th wind turbine in the time window, η is the frequency modulation power change limit ratio, P N is the rated installed capacity of the wind turbine group, is the average theoretical power that can be generated by the i-th wind turbine in the time window, and m is the total number of wind turbines participating in the frequency response.

6. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1, characterized in that: In S5, the power-limited operation mode adopts a generator overspeed operation mode, and when the wind turbine is already at the maximum speed, a pitch angle adjustment mode is adopted.

7. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1, characterized in that: In S6, the output power adjustment amplitude of the wind turbine generator set participating in the frequency response is: Among them, K f is the primary frequency modulation active frequency modulation coefficient, f is the grid frequency, T J is the equivalent inertia time constant, t is time, P N is the rated installed capacity of the wind turbine group, f N is the rated frequency of the power grid.

8. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 7 is characterized in that: Primary frequency modulation active frequency modulation coefficient K f The value range is [10,50], and the equivalent inertia time constant T J The value range is [8,12].

9. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1, characterized in that: In S6, the step of calculating the output power of each wind turbine generator system participating in the frequency response according to the current output power and the theoretically available power thereof includes: The output power of the frequency response of the i-th wind turbine is Where P oi is the current output power of the i-th wind turbine, is the average theoretical power that can be generated by the i-th wind turbine in the time window, m is the total number of wind turbines participating in the frequency response, and ΔP is the output power adjustment amplitude of the wind turbines participating in the frequency response.

10. The method for wind turbine group frequency response based on laser radar wind measurement according to claim 1, characterized in that: In S7, after the frequency response ends, each wind turbine generator system participating in the frequency response resumes power output in multiple rounds according to its power generation capacity.

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