CN115765042A - Draught fan primary frequency modulation method based on power grid frequency response maximum point moment correspondence - Google Patents

Abstract

The invention discloses a primary frequency modulation method of a fan based on the time correspondence of a power grid frequency response maximum point, which comprises the following steps: detecting whether a frequency event occurs or not, and recording the occurrence time; calculating the moment of the minimum value point of the power grid frequency response under the excitation of the step load power; analyzing the relation between the power grid frequency response maximum value point moment under TLIC wind power excitation and the power grid frequency response minimum value point moment under step load power excitation; estimating the time of the maximum point of the power grid frequency response under the excitation of TLIC wind power, and calculating the delay starting time of the TLIC method of the fan based on the corresponding principle of the maximum point time; and realizing primary frequency modulation control of the fan based on the most-valued point moment according to the delay starting time. The method provided by the invention can realize the correspondence of the frequency response maximum value point under the TLIC wind power excitation and the minimum value point under the load sudden increase, further improve the lowest point of the power grid frequency and improve the frequency modulation effect of the fan participating in the power grid.

Description

A wind turbine primary frequency regulation method based on the time corresponding to the most value point of the grid frequency response

technical field

The invention belongs to the field of fan control, in particular to a fan primary frequency modulation control method and system based on the time corresponding to the maximum value point of the frequency response of the grid.

Background technique

With the sharp increase in wind power penetration, the proportion of conventional synchronous units has been decreasing, and the inertia of the power system has been significantly reduced. There is an urgent need for wind turbines to participate in primary frequency regulation of the power grid. According to whether the output electromagnetic power of the fan is related to the grid frequency, the existing primary frequency control of the fan can be roughly divided into two categories: the primary frequency control of real-time response to frequency changes, such as virtual inertia control and droop control; and the primary frequency control of the preset power curve , such as Stepping Inertial Control (SIC) and Torque Limiting Inertial Control (TLIC).

The primary frequency modulation control of the preset power curve generally includes two stages of frequency support and wind rotor speed recovery. When a sudden load frequency event occurs, the SIC method increases the wind power step by step to support the active power balance of the grid. Only from the perspective of power grid frequency response superposition compensation, the form of wind power step increase can produce the best compensation effect on sudden load increase in the frequency support stage. In particular, if the magnitude of the wind power increase is equal to the load surge, the frequency response component corresponding to the wind power during the frequency support phase will fully compensate for the grid frequency drop caused by the load surge, that is, the grid frequency remains constant.

However, due to the limited kinetic energy buffered by the wind rotor, the step reduction of wind power by the SIC method at the end of the frequency support will lead to the well-known grid secondary frequency dip (SFD). For this reason, how to cooperate with the primary frequency regulation of the wind turbine and the synchronous unit to alleviate the secondary drop of the grid frequency has become one of the focuses of existing research. The main progress can be summarized into two aspects, the improvement method based on SIC and the method of wind power showing slow down characteristics. However, the application of the TLIC method substantially changes the change type of wind power, which no longer has the same step form as the load sudden increase, and the maximum point of the frequency response component obtained by the TLIC method excitation is always earlier than the minimum load sudden increase. The value point makes the maximum effect of wind turbine frequency regulation on the grid frequency support appear prematurely, resulting in the inability to fully exert the compensation effect on the grid frequency drop caused by the sudden load increase.

Contents of the invention

The purpose of the present invention is to solve the problems existing in the above-mentioned prior art, and provide a fan primary frequency modulation control method and system based on the time corresponding to the maximum value point of the frequency response of the power grid. By delaying the start-up time of the wind turbine TLIC method, the correspondence between the maximum point of frequency response under TLIC wind power excitation and the minimum point under sudden load increase is realized, the lowest point of grid frequency is further increased, and the effect of wind turbines participating in grid frequency regulation is improved.

The technical solution to achieve the purpose of the present invention is: a method for primary frequency regulation of fans based on the time corresponding to the maximum value point of the frequency response of the power grid. The method includes the following steps:

Step 1, detect the frequency event, and record the occurrence time t ₀ ;

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

Further, step 1 is specifically: detecting the frequency deviation of the power grid, if it exceeds the preset threshold value |Δf| _thd , it is considered that a sudden load increase or a generator cut-off event has occurred in the power grid, that is, a frequency event, and the occurrence time t ₀ is recorded .

具体过程包括：Further, in step 2, calculate the minimum value point time of the grid frequency response under step load power excitation

The specific process includes:

For the load sudden increase event, the grid frequency response Δf _L under step load power excitation is:

Δf _L (t) = ΔP _L h _step (t)

In the formula, ΔP _L is the load step disturbance amplitude, H is the system inertia time constant, D is the load damping coefficient, R is the droop coefficient of the governor, T is the time constant of the governor, F is the high-pressure turbine power accounted for by the total steam turbine The ratio of power, K is the mechanical power gain coefficient;

Then the minimum value point of the grid frequency response under step load power excitation is

Further, the step 3 obtains the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the grid frequency response under the excitation of the step load power, specifically including:

The approximate grid frequency response Δf _W under simplified TLIC wind power excitation is shown in the following formula, which is expressed as a superposition of frequency responses corresponding to a step signal and two ramp signals:

Δf _W (t)＝ΔP _W0 h _step (t)u(t)+K _Pt h _ramp (t)u(t)-K _Pt h _ramp (tt ₁ )u(tt ₁ )

In the formula, ΔP _W0 is the initial support power increment of the fan TLIC method, ΔP _W0 =P _Tlim (ω ₀ )-P _W0 , P _Tlim (ω ₀ ) is the power corresponding to the maximum torque at the initial speed ω ₀ , P _W0 is the initial electromagnetic power of the fan; K _Pt is the slope of the segmented curve, that is, the rate of change of wind power; t ₁ is the time for the simplified wind power to drop to the electromagnetic power at the equilibrium point; u(t) is a unit step signal, h _step (t) is the unit step response, h _ramp (t) is the unit ramp response;

Deriving the above formula, the rate of change of the frequency response corresponding to the simplified TLIC wind power is obtained:

处的符号说明电网频率响应最大值点时刻

与电网频率响应最小值点时刻

两者的关系，根据t₁和

的关系分为如下两种情况：By analyzing Δf' _W (t) in

The symbol at indicates the time of the maximum point of the grid frequency response

and grid frequency response minimum point moment

The relationship between the two, according to t ₁ and

The relationship is divided into the following two situations:

时，有(1) when

when there is

以及K_P-t＜0，所以

because

and K _Pt < 0, so

时，有(2) when

when there is

是递增的，同时

所以

Because h _step (t) is in

is increasing, while

so

在任意参数的TLIC风电功率激励下都是成立的，Δf_W(t)在

内至少存在一个极大值点，且第一个极大值点为最大值点，则有：therefore,

It is true under any parameter of TLIC wind power excitation, Δf _W (t) in

There is at least one maximum point in , and the first maximum point is the maximum point, then:

Further, step 4 specifically includes:

估计值；Step 4-1, according to the simplified TLIC wind power, use the Newton-Raphson method to numerically solve to get

estimated value;

Step 4-2, calculate the delayed start time of the fan TLIC method

在

时刻启动风机TLIC调频控制，实现TLIC风电功率激励下频率响应最大值点和负荷突增下最小值点的对应。Further, step 5 specifically includes: based on the estimated delayed start time

exist

Start the TLIC frequency modulation control of the fan at all times to realize the correspondence between the maximum point of frequency response under TLIC wind power excitation and the minimum point under sudden load increase.

The present invention provides a fan primary frequency regulation system based on the time corresponding to the maximum value point of the frequency response of the power grid. The system includes:

The first module is used to detect a frequency event, that is, a sudden load increase or a generator cut-off event, and record the occurrence time t ₀ ;

并基于TLIC风电功率激励下频率响应最大值点时刻与突增负荷功率激励下频率响应最小值点的对应关系，计算风机TLIC方法的延迟启动时间

The second module is used to estimate the maximum point of the grid frequency response under TLIC wind power excitation

And based on the corresponding relationship between the maximum point of the frequency response under the excitation of TLIC wind power and the minimum point of the frequency response under the excitation of sudden load power, the delayed start time of the wind turbine TLIC method is calculated

时刻，启动TLIC方法，设定风机电磁功率指令；The third module, for the

time, start the TLIC method, and set the electromagnetic power command of the fan;

The fourth module is used to restore the speed of the fan to the initial optimal speed by reducing the electromagnetic power after the fan runs at a stable equilibrium point.

A computer device, including a memory, a processor, and a computer program stored on the memory and operable on the processor. When the processor executes the computer program, the following steps are implemented:

Step 1, detect the frequency event, and record the occurrence time t ₀ ;

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

A computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

Step 1, detect the frequency event, and record the occurrence time t ₀ ;

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

Compared with the prior art, the present invention has the remarkable advantages of:

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

2) By delaying the start of fan frequency modulation control, the lowest point of grid frequency is further improved without affecting the dynamic speed of fan speed, and the effect of wind power frequency modulation is improved.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a flow chart of the primary frequency regulation control of the fan based on the time corresponding to the maximum point of the grid frequency response in the present invention.

Fig. 2 is a schematic diagram of torque-limited inertial control of a fan in an embodiment.

Fig. 3 is a schematic diagram of TLIC wind power and its approximation in an embodiment.

Fig. 4 is a schematic diagram of the time of the maximum point of the frequency response under different approximate wind power excitations in an embodiment.

Fig. 5 is a schematic diagram of grid frequency response components under two power excitations in an embodiment.

Fig. 6 is a schematic diagram of an improvement idea based on the time corresponding to the maximum/minimum value point of the frequency response in an embodiment.

Fig. 7 is a schematic block diagram of TLIC control based on the time corresponding to the maximum value point of the grid frequency response in an embodiment.

Fig. 8 is an embodiment of the frequency modulation effects of wind turbines in the three methods of not participating in frequency modulation, TLIC without delay, and TLIC corresponding to the maximum value point, where Figures (a) to (d) are grid frequency, Fan output, synchronous unit output and wind rotor speed.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. Implying their relative importance or implying the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist , nor within the scope of protection required by the present invention.

In one embodiment, with reference to FIG. 1 , a method for primary frequency regulation control of wind turbines based on the moment corresponding to the maximum point of the frequency response of the power grid is provided, and the method includes the following steps:

Step 1: Detect the _{frequency deviation} of the power grid. If it exceeds the preset threshold value |Δf|

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

具体过程包括：Further, in one of the embodiments, in step 2, the calculation of the minimum value point of the grid frequency response under step load power excitation is

The specific process includes:

For the load sudden increase event, the grid frequency response Δf _L under step load power excitation is:

Δf _L (t) = ΔP _L h _step (t)

In the formula, ΔP _L is the load step disturbance amplitude, H is the system inertia time constant, D is the load damping coefficient, R is the droop coefficient of the governor, T is the time constant of the governor, F is the high-pressure turbine power accounted for by the total steam turbine The ratio of power, K is the mechanical power gain coefficient;

Then the minimum value point of the grid frequency response under step load power excitation is

It can be seen from the above formula that the extreme value point of the grid frequency response under the step power excitation is fixed, which is only related to the system parameters (H, D, R, T, F, K) and has nothing to do with the step excitation amplitude ΔP _L .

Further, in one of the embodiments, referring to Fig. 2 and Fig. 3, step 3 obtains the torque-limited inertial control TLIC wind power excitation, the grid frequency response maximum point moment and the grid frequency response under step load power excitation The relationship between the minimum point moments, specifically including:

The approximate grid frequency response Δf _W under simplified TLIC wind power excitation is shown in the following formula, which is expressed as a superposition of frequency responses corresponding to a step signal and two ramp signals:

Δf _W (t)＝ΔP _W0 h _step (t)u(t)+K _Pt h _ramp (t)u(t)-K _Pt h _ramp (tt ₁ )u(tt ₁ )

In the formula, ΔP _W0 is the initial support power increment of the fan TLIC method, ΔP _W0 =P _Tlim (ω ₀ )-P _W0 , P _Tlim (ω ₀ ) is the power corresponding to the maximum torque at the initial speed ω ₀ , P _W0 is the initial electromagnetic power of the fan; K _Pt is the slope of the segmented curve, that is, the rate of change of wind power; t ₁ is the time for the simplified wind power to drop to the electromagnetic power at the equilibrium point; u(t) is a unit step signal, h _step (t) is the unit step response, h _ramp (t) is the unit ramp response;

Deriving the above formula, the rate of change of the frequency response corresponding to the simplified TLIC wind power is obtained:

处的符号说明电网频率响应最大值点时刻

与电网频率响应最小值点时刻

两者的关系，根据t₁和

的关系分为如下两种情况：By analyzing Δf' _W (t) in

The symbol at indicates the time of the maximum point of the grid frequency response

and grid frequency response minimum point moment

The relationship between the two, according to t ₁ and

The relationship is divided into the following two cases:

时，有(1) when

when there is

以及K_P-t＜0，所以

because

and K _Pt < 0, so

时，有(2) when

when there is

是递增的，同时

所以

Because h _step (t) is in

is increasing, while

so

在任意参数的TLIC风电功率激励下都是成立的，Δf_W(t)在

内至少存在一个极大值点，且第一个极大值点为最大值点，则有：therefore,

It is true under any parameter of TLIC wind power excitation, Δf _W (t) in

There is at least one maximum point in , and the first maximum point is the maximum point, then:

始终成立，且与具体参数设定无关。TLIC风电功率激励下电网频率响应最大值点时刻始终早于阶跃负荷对应的频率最小值点，这使得TLIC方法提升频率最低点的最佳补偿效果会提早出现，从而影响到风机TLIC方法的调频效果。To sum up, under the wind power excitation based on segmented form,

It is always true and has nothing to do with the specific parameter settings. Under TLIC wind power excitation, the maximum point of the grid frequency response is always earlier than the minimum frequency point corresponding to the step load, which makes the best compensation effect of the TLIC method to increase the frequency minimum point appear earlier, thus affecting the frequency regulation of the wind turbine TLIC method Effect.

是固定的，将估计启动风机TLIC方法的延迟启动时间

转为估计TLIC风电功率激励下电网频率响应最大值点时刻，即估计

步骤4具体包括：Furthermore, in one of the embodiments, due to the step load power excitation, the grid frequency response minimum point moment

is fixed and will estimate the delayed start time for the TLIC method of starting the fan

To estimate the moment of the maximum point of the grid frequency response under TLIC wind power excitation, that is, to estimate

Step 4 specifically includes:

估计值；Step 4-1, according to the simplified TLIC wind power, use the Newton-Raphson method to numerically solve to get

estimated value;

Step 4-2, calculate the delayed start time of the fan TLIC method

在

时刻启动风机TLIC调频控制，实现TLIC风电功率激励下频率响应最大值点和负荷突增下最小值点的对应，以最大程度补偿负荷突增造成的电网频率最低点。Further, in one of the embodiments, step 5 specifically includes: based on the estimated delayed start time

exist

Start the TLIC frequency modulation control of the wind turbine at all times to realize the correspondence between the maximum point of the frequency response under the TLIC wind power excitation and the minimum point under the sudden load increase, so as to compensate the lowest point of the grid frequency caused by the sudden load increase to the greatest extent.

In one embodiment, a wind turbine primary frequency regulation system based on the moment corresponding to the maximum point of the grid frequency response is provided, and the system includes:

The first module is used to detect a frequency event, that is, a sudden load increase or a generator cut-off event, and record the occurrence time t ₀ ;

并基于TLIC风电功率激励下频率响应最大值点时刻与突增负荷功率激励下频率响应最小值点的对应关系，计算风机TLIC方法的延迟启动时间

The second module is used to estimate the maximum point of the grid frequency response under the simplified TLIC wind power excitation

And based on the corresponding relationship between the maximum point of the frequency response under the excitation of TLIC wind power and the minimum point of the frequency response under the excitation of sudden load power, the delayed start time of the wind turbine TLIC method is calculated

时刻，启动TLIC方法，设定风机电磁功率指令；The third module, for the

time, start the TLIC method, and set the electromagnetic power command of the fan;

The fourth module is used to restore the speed of the fan to the initial optimal speed by reducing the electromagnetic power after the fan runs at a stable equilibrium point.

For specific limitations on the primary frequency regulation system of wind turbines based on the time corresponding to the maximum value point of the grid frequency response, please refer to the above-mentioned definition of the primary frequency regulation method of wind turbines based on the time corresponding to the maximum point of the grid frequency response, and will not be repeated here. Each module in the fan primary frequency regulation system based on the time corresponding to the maximum value point can be realized in whole or in part by software, hardware and combinations thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, and can also be stored in the memory of the computer device in the form of software, so that the processor can invoke and execute the corresponding operations of the above-mentioned modules.

In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and operable on the processor. When the processor executes the computer program, the following steps are implemented:

Step 1, detect the frequency event, and record the occurrence time t ₀ ;

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

For the specific definition of each step, please refer to the above-mentioned definition of the primary frequency regulation method of the wind turbine based on the moment of the grid frequency response maximum point, and will not be repeated here.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

Step 1, detect the frequency event, and record the occurrence time t ₀ ;

Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power;

并基于电网频率响应最值点时刻对应关系计算风机TLIC方法的延迟启动时间

Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

实现基于最值点时刻对应的风机一次调频控制。Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point.

For the specific definition of each step, please refer to the above-mentioned definition of the primary frequency regulation method of the wind turbine based on the moment of the grid frequency response maximum point, and will not be repeated here.

As a specific example, in one of the embodiments, the present invention is further verified and explained.

In this embodiment, the open-source professional wind turbine simulation software FAST (Fatigue, Aerodynamics, Structures, and Turbulence) provided by the National Renewable Energy Laboratory (NREL) of the United States is used to simulate and verify the effect. Among them, the wind power system dynamic model experiment platform mainly includes three parts: fan simulator, synchronous machine simulator and regenerative load. The main parameters of the experiment platform are shown in Table 1 below.

Table 1 The main parameters of the dynamic model experiment platform

The present invention is based on the fan primary frequency modulation control method corresponding to the most value point time, including the following content:

1. Detect whether the frequency event occurs, and record the occurrence time t ₀ ;

具体包括：2. Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Specifically include:

For the load sudden increase event, the grid frequency response Δf _L under step load power excitation is:

Δf _L (t) = ΔP _L h _step (t)

In the formula, ΔP _L is the load step disturbance amplitude, H is the system inertia time constant, D is the load damping coefficient, R is the droop coefficient of the governor, T is the time constant of the governor, F is the high-pressure turbine power accounted for by the total steam turbine The ratio of power, K is the mechanical power gain coefficient. Under step load power excitation, the minimum point of grid frequency response is

3. Analyze the relationship between the moment of the maximum point of the grid frequency response under the excitation of TLIC wind power and the moment of the minimum point of the grid frequency response under the excitation of step load power, including:

The actual TLIC wind power is replaced by the approximate TLIC wind power shown by the dotted line in Fig. 3. The approximate (simplified) grid frequency response Δf _W under TLIC wind power excitation is as follows,

Δf _W (t)＝ΔP _W0 h _step (t)u(t)+K _Pt h _ramp (t)u(t)-K _Pt h _ramp (tt ₁ )u(tt ₁ )

In the formula, ΔP _W0 is the initial support power increment of the wind turbine TLIC method, ΔP _W0 =P _Tlim (ω ₀ )-P _W0 ; K _Pt is the slope of the segmented curve, that is, the rate of change of wind power power; t ₁ is the simplified wind power The time at which the power falls to the electromagnetic power at equilibrium point C.

在任意参数设定的简化TLIC风电功率激励下都是成立的。因此，如图4和图5所示，任意参数设定下的TLIC风电功率激励下电网频率响应最大值点时刻始终早于阶跃负荷对应的频率最小值点，即because

It is established under the simplified TLIC wind power excitation with arbitrary parameter settings. Therefore, as shown in Figure 4 and Figure 5, the maximum point of the grid frequency response under the excitation of TLIC wind power under any parameter setting is always earlier than the minimum frequency point corresponding to the step load, that is,

并基于最值点时刻对应原则计算风机TLIC方法的延迟启动时间

具体包括：4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the principle of the corresponding time of the most value point

Specifically include:

估计值，采用牛顿-拉夫逊方法来数值求解

并将

初值设置为0。基于图6所示的电网频率响应最值点时刻相对应的原则，可以得到

和

的数量关系为

的关系，估计得到启动TLIC方法的延时时间

According to the approximate TLIC wind power

Estimated values, solved numerically using the Newton-Raphson method

and will

The initial value is set to 0. Based on the principle of corresponding to the most value point of the frequency response of the power grid shown in Figure 6, it can be obtained

and

The quantitative relationship is

relationship, estimate the delay time to start the TLIC method

5. According to the delayed start time, realize the primary frequency regulation control of the fan based on the moment of the maximum value point of the frequency response of the power grid, specifically including:

时刻启动风机TLIC调频控制，实现TLIC风电功率激励下频率响应最大值点和负荷突增下最小值点的对应，以最大程度补偿负荷突增造成的电网频率最低点。完整的基于电网频率响应最值点时刻对应的风机一次调频方法原理框图如图7所示，包括频率事件监测模块、延迟时间估计模块、TLIC频率支撑模块、风轮转速恢复模块和MPPT模块。Based on the estimated delayed start time, the

Start the TLIC frequency modulation control of the wind turbine at all times to realize the correspondence between the maximum point of the frequency response under the TLIC wind power excitation and the minimum point under the sudden load increase, so as to compensate the lowest point of the grid frequency caused by the sudden load increase to the greatest extent. The complete principle block diagram of the wind turbine primary frequency regulation method based on the grid frequency response maximum point moment is shown in Figure 7, including the frequency event monitoring module, the delay time estimation module, the TLIC frequency support module, the wind rotor speed recovery module and the MPPT module.

6. In the experimental scenario where the constant wind speed is 10m/s, the wind power penetration rate is about 60%, and the regenerative load has a load sudden increase frequency event (load sudden increase is 1.5kW) at the time of 300s. Figure 8 shows the grid frequency, fan output power and wind rotor speed under the three methods of not participating in frequency regulation, TLIC without delay, and TLIC considering delay support.

Table 2 Comparison of frequency modulation effect indicators

By analyzing the frequency modulation effect indicators in Figure 8(a) and Table 2, it can be seen that on the basis of the TLIC method, by delaying the start-up of the fan frequency modulation control, the maximum point of the frequency response under TLIC wind power excitation and the minimum point under sudden load increase are realized. Corresponding to the value points, the lowest point of the grid frequency is raised from -0.5658Hz to -0.4959Hz, and the maximum frequency change rate at the initial stage after the occurrence of the frequency event is the same as that under the MPPT method. It can be seen from the electromagnetic power of the fan and the speed of the wind rotor in Figure 8(b) and (d), that delaying the start of the TLIC frequency modulation control of the fan will not affect the electromagnetic power and speed dynamics of the fan, but only delay it backward. It can be seen that the method proposed by the present invention can further increase the lowest point of the power grid frequency without affecting the dynamic speed of the fan.

The above simulation experiment results show that the primary frequency modulation control method of the wind turbine based on the time corresponding to the maximum value point of the frequency response of the power grid proposed by the present invention can realize the correspondence between the maximum point of the frequency response under the excitation of TLIC wind power and the minimum point under the sudden increase of load, Further increase the lowest point of grid frequency and improve the effect of wind power frequency regulation.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention.

Claims (9)

1. A fan primary frequency regulation method based on grid frequency response maximum point moment corresponding, it is characterized in that, described method comprises the following steps: Step 1, detect the frequency event, and record the occurrence time t ₀ ; Step 2: Calculating the moment of the minimum value point of the grid frequency response under step load power excitation

Step 3. Obtain the relationship between the moment of the maximum point of the grid frequency response under the excitation of the wind power by the torque-limited inertial control TLIC and the moment of the minimum point of the frequency response of the grid under the excitation of the step load power; Step 4. Estimate the time of the maximum point of the grid frequency response under TLIC wind power excitation

And calculate the delayed start time of the fan TLIC method based on the corresponding relationship of the grid frequency response maximum point time

Step 5, according to the delay start time

Realize the primary frequency control of the fan based on the time corresponding to the maximum value point. 2. The primary frequency regulation method of wind turbines based on the time corresponding to the maximum value point of the frequency response of the power grid according to claim 1, wherein the step 1 is specifically: detecting the frequency deviation of the power grid, and if it exceeds the preset threshold value |Δf| _thd , it is considered A sudden load increase or a generator cut-off event occurs in the power grid, that is, a frequency event, and the occurrence time t ₀ is recorded. 3. The fan primary frequency regulation method based on the grid frequency response maximum point time according to claim 1, characterized in that, step 2 calculates the power grid frequency response minimum point time under step load power excitation

The specific process includes: For the load sudden increase event, the grid frequency response Δf _L under step load power excitation is: Δf _L (t) = ΔP _L h _step (t)

In the formula, ΔP _L is the load step disturbance amplitude, H is the system inertia time constant, D is the load damping coefficient, R is the droop coefficient of the governor, T is the time constant of the governor, F is the high-pressure turbine power accounted for by the total steam turbine The ratio of power, K is the mechanical power gain coefficient; Then the minimum value point of the grid frequency response under step load power excitation is

4. The primary frequency regulation method for wind turbines based on the grid frequency response maximum point moment according to claim 3, characterized in that, in step 3, the maximum value point of the grid frequency response is obtained under the excitation of the torque-limited inertial control TLIC wind power power The relationship between the moment and the moment of the minimum point of the grid frequency response under step load power excitation, specifically includes: The approximate grid frequency response Δf _W under simplified TLIC wind power excitation is shown in the following formula, which is expressed as a superposition of frequency responses corresponding to a step signal and two ramp signals: Δf _W (t)＝ΔP _W0 h _step (t)u(t)+K _Pt h _ramp (t)u(t)-K _Pt h _ramp (tt ₁ )u(tt ₁ ) In the formula, ΔP _W0 is the initial support power increment of the fan TLIC method, ΔP _W0 =P _Tlim (ω ₀ )-P _W0 , P _Tlim (ω ₀ ) is the power corresponding to the maximum torque at the initial speed ω ₀ , P _W0 is the initial electromagnetic power of the fan; K _Pt is the slope of the segmented curve, that is, the rate of change of wind power; t ₁ is the time for the simplified wind power to drop to the electromagnetic power at the equilibrium point; u(t) is a unit step signal, h _step (t) is the unit step response, h _ramp (t) is the unit ramp response; Deriving the above formula, the rate of change of the frequency response corresponding to the simplified TLIC wind power is obtained:

By analyzing Δf' _W (t) in

The symbol at indicates the time of the maximum point of the grid frequency response

and grid frequency response minimum point moment

The relationship between the two, according to t ₁ and

The relationship is divided into the following two situations: (1) when

when there is

because

and K _Pt < 0, so

(2) when

when there is

Because h _step (t) is in

is increasing, while

so

therefore,

It is true under any parameter of TLIC wind power excitation, Δf _W (t) in

There is at least one maximum point in , and the first maximum point is the maximum point, then:

5. The fan primary frequency regulation method based on the grid frequency response maximum point moment according to claim 4, characterized in that step 4 specifically includes: Step 4-1, according to the simplified TLIC wind power, use the Newton-Raphson method to numerically solve to obtain

estimated value; Step 4-2, calculate the delayed start time of the fan TLIC method

6. The primary frequency regulation method for wind turbines based on the time corresponding to the maximum point of the grid frequency response according to claim 5, characterized in that step 5 specifically includes: based on the estimated delayed start time

exist

Start the TLIC frequency modulation control of the fan at all times to realize the correspondence between the maximum point of frequency response under TLIC wind power excitation and the minimum point under sudden load increase. 7. The fan primary frequency regulation system based on the grid frequency response maximum point moment corresponding to the method according to any one of claims 1 to 6, characterized in that the system includes: The first module is used to detect a frequency event, that is, a sudden load increase or a generator cut-off event, and record the occurrence time t ₀ ; The second module is used to estimate the maximum point of the grid frequency response under the simplified TLIC wind power excitation

And based on the corresponding relationship between the maximum point of the frequency response under the excitation of TLIC wind power and the minimum point of the frequency response under the excitation of sudden load power, the delayed start time of the wind turbine TLIC method is calculated

The third module, for the

time, start the TLIC method, and set the electromagnetic power command of the fan; The fourth module is used to restore the speed of the fan to the initial optimal speed by reducing the electromagnetic power after the fan runs at a stable equilibrium point. 8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, characterized in that, when the processor executes the computer program, any one of claims 1 to 6 is realized. A step of said method. 9. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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