WO2022198909A1

WO2022198909A1 - Operation control method and system for wind turbine under extreme wind conditions

Info

Publication number: WO2022198909A1
Application number: PCT/CN2021/113617
Authority: WO
Inventors: 金强; 蔡安民; 林伟荣
Original assignee: 中国华能集团清洁能源技术研究院有限公司
Priority date: 2021-03-26
Filing date: 2021-08-19
Publication date: 2022-09-29
Also published as: CN112796943A; CN112796943B

Abstract

An operation control method for a wind turbine under extreme wind conditions. Speed, which is the most reliable measurement signal of a wind turbine, is used to determine, on the basis of the rotational speed control effect and trend thereof at the current moment, whether the turbine has encountered extreme wind conditions of changes in wind speed and direction, so as to enter a low load mode to protect thereby the turbine. By detecting the difference in the rotational speed of the wind turbine at previous and subsequent moments and the differential product thereof, it is determined within a short time period whether the wind turbine has encountered extreme wind conditions. If a preset threshold is exceeded, the turbine enters a power-limiting state. Said method can prevent a turbine from experiencing extreme loads to the greatest extent and improve the operation safety of the turbine under extreme wind conditions. The turbine power operation mode is controlled by the turbine operation state, thereby improving the operation safety of a wind turbine under extreme wind conditions.

Description

An operation control method and system for wind turbines under extreme wind conditions

technical field

The invention belongs to the field of wind power generation, and relates to an operation control method and system for a wind generator set under extreme wind conditions.

Background technique

The wind wheel of the horizontal axis wind turbine absorbs the wind energy and rotates, and then drives the connected wind turbine to rotate and generate electricity. However, in the face of some extreme turbulent wind conditions, the wind speed and wind direction will change drastically in a short period of time, and the rotational speed of the wind turbine and the force of the various components will also fluctuate greatly, so the wind turbine will suffer from extreme loads, which is not conducive to the wind turbine. operation. Therefore, it is necessary to adjust the unit operation control strategy to minimize the unit load under extreme wind conditions.

The existing technical solutions for this problem are roughly as follows: according to the current working state of the wind turbine, determine a turbulence intensity estimation method suitable for the current working state, and determine the turbulence intensity based on the determined turbulence intensity estimation method; The generator set enters the reduced load operation mode. That is to say, the existing control strategies for extreme wind conditions include the introduction of wind speed, engine room acceleration, etc. as the basis for the operation control strategy of the unit, but the measurement of wind speed, the zero drift of engine room acceleration, and the reliability of measuring equipment make the measurement of this method difficult. When the data signal is introduced into the control algorithm, the actual control effect deviation may exist due to the measurement deviation.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art that the wind turbine operation control measurement deviation is large under extreme wind conditions, and to provide an operation control method and system for wind turbines under extreme wind conditions.

In order to achieve the above object, the present invention adopts the following technical solutions to be realized:

An operation control method for wind turbines under extreme wind conditions, comprising the following steps:

Step 1) Obtain the speed difference of the wind turbine at the current moment and the speed difference at the previous moment, and obtain the speed acceleration of the wind turbine;

Step 2) based on the rotational speed difference and rotational speed acceleration of step 1), obtain the operating value of the wind turbine;

Step 3) obtaining a preset trigger threshold of the wind turbine control method;

Step 4) Compare the operating value of step 2) with the trigger threshold value of step 3):

In state 1, if the operating value of the wind turbine is less than the trigger threshold, the current power setting value P1 will remain unchanged;

In state 2, if the operating value of the wind turbine is greater than the trigger threshold, the power setting value is reduced to P2. At this time, the wind turbine enters the power-limited state, and the operating time of the limited-power state is calculated. When the operating time of the limited-power state is less than or equal to the preset During the set control cycle, the power-limited state is maintained; when the running time of the power-limited state is greater than the preset control cycle, the power-limited state is terminated and the power setting value P1 is returned.

Preferably, in step 1), the process of obtaining the speed difference at the current moment is as follows: first obtain the speed setting value of the wind turbine, then obtain the speed value of the wind turbine at the current moment, filter the speed value of the wind turbine at the current moment, and calculate The difference between the speed setting value of the wind turbine and the filter-processed speed value at the current moment is used to obtain the speed difference of the wind turbine at the current moment;

The acquisition process of the speed difference at the last moment is: obtain the speed value of the wind turbine at the last moment, filter the speed value of the wind turbine at the last moment, calculate the speed setting value of the wind turbine and the last moment after filtering. The difference between the speed values of , obtains the speed difference of the wind turbine at the previous moment.

Further preferably, the filtering is performed by using a low-pass filtering method for signal filtering.

Preferably, the calculation process of the rotational speed acceleration in step 1) is as follows: calculating the difference between the rotational speed difference of the wind turbine at the current moment and the rotational speed difference of the wind turbine at the previous moment, and obtaining the difference between the rotational speeds of the wind turbines before and after, based on the The speed difference of the wind turbine at the moment and the preset control period constant are used to calculate the speed acceleration of the wind turbine.

Preferably, the operating value of the wind turbine in step 2) is obtained by multiplying the rotational speed acceleration of the wind turbine by the difference in rotational speed of the wind turbine at the current moment.

Preferably, in step 3), the triggering threshold of the control method is obtained through the following process: setting a detection period, obtaining the pitch angle of the wind turbine within the detection period, and calculating the speed difference and rotational speed of the wind turbine corresponding to the pitch angle at the current moment by means of interpolation The difference-differential product presets the threshold to obtain the triggering threshold of the control method.

Preferably, the preset control period in step 4) is 300-400s;

The process of reducing the power setting value in the state 2 of step 4) is performed with a slope of -150kW/s.

An operation control system for wind turbines under extreme wind conditions, comprising:

The rotational speed acquisition module is used to obtain the rotational speed value of the wind turbine at the current moment and the previous moment;

The data processing module interacts with the rotational speed acquisition module. Based on the rotational speed values of the wind turbine at the current moment and the previous moment, after calculation and processing, the rotational speed difference of the wind turbine at the current moment and the rotational speed difference at the previous moment are obtained, and the rotational speed of the wind turbine is obtained. Acceleration, get the operating value of the wind turbine, and get the preset operating threshold of the wind turbine;

The abnormality judging module interacts with the data processing module, compares the operating value of the wind turbine with the trigger threshold of the preset control method of the wind turbine, and judges the operating state of the wind turbine.

Preferably, the abnormality judgment module includes operating value judgment and time judgment; the operating value judgment is used for judging the relationship between the operating value and the operating threshold, and according to the judgment result, an instruction is given to the power setting value; the time judgment is used for judging the limit The relationship between the running time of the power state and the preset control cycle, and according to the judgment result, the command is issued to the limited power state.

Preferably, the device used by the abnormality judging module is a PLC controller.

Compared with the prior art, the present invention has the following beneficial effects:

The invention discloses an operation control method for wind turbines under extreme wind conditions. The rotation speed, the most reliable measurement signal of the wind turbines, is adopted, and the control effect and trend of the rotation speed at the current moment are used to judge whether the turbines encounter extreme wind speed and wind direction changes. wind conditions, thus entering a low load mode to protect the unit. By detecting the difference between the rotational speed of the wind turbine before and after the time and the product of its differential, it can be judged whether the wind turbine has encountered extreme wind conditions in a relatively short period of time. The unit experiences extreme loads, improving the operational safety of the unit in extreme wind conditions. The power operation mode of the unit is controlled by the operation state of the unit, so as to improve the operation safety of the wind turbine under extreme wind conditions. The invention adopts the rotational speed of the wind turbine as the control input, overcomes the deviation of the control effect caused by the inaccurate and unreliable measurement caused by the measurement signals such as the wind speed or the acceleration of the engine room being easily interfered in the traditional method, and innovatively adopts the rotational speed difference of the wind turbine and its differential. The product represents the fluctuation degree of the unit's rotational speed as a judgment condition.

Further, the triggering condition of the control method in step 3) is the comparison between the actual operating value and the threshold value, the threshold value calculation is performed by a table look-up method, each pitch angle corresponds to a threshold value, and the corresponding threshold value is queried by the pitch angle to ensure accurate control. On the premise, the processing speed of the method of the present invention can be improved.

Further, the original signal is not suitable for measuring the rotational speed of the wind turbine used in the present invention due to the measurement device or estimation algorithm, etc., and it needs to be filtered to avoid unnecessary measurement interference signals affecting the control effect.

Further, after the unit determines that the extreme wind conditions are established and enters the power-limited operation mode, it needs to maintain for a period of time, such as 300-400 seconds, to prevent the unit from frequently switching between the normal power generation mode and the power-limited mode.

Further, enter the power limit mode, the power setting value P1 is set to P2 with deltaP as the slope, so as to avoid the impact of the unit operating state caused by the change of the power setting value in one cycle.

The invention also discloses an operation control system for wind turbines under extreme wind conditions, which adopts the measurement of the rotational speed of the wind turbine as an input, and the rotational speed of the wind turbine is one of the most reliable measurement signals among the control input signals of the wind turbine, so as to avoid the occurrence of damage caused by the nacelle. The judgment conditions caused by the deviation of the wind speed measured by the anemometer or the acceleration of the cabin by the vibration sensor are not accurate enough. Using the differential product of the measured wind turbine speed difference and the speed difference as the judgment condition, it can effectively identify whether the wind turbine is subject to extreme wind conditions at any time. The method of limiting power is adopted to reduce the output of the unit under extreme wind conditions while avoiding the extreme load of the unit.

Description of drawings

FIG. 1 is a flow chart of an operation control method for a wind turbine under extreme wind conditions according to the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

In the existing technical solution, the cabin anemometer is used to measure the wind speed or the vibration sensor is used to measure the cabin acceleration. The sensors are located outside the cabin or in the cabin. Due to the continuous change of the wind speed, the cabin and the tower are in different degrees of vibration, and the measurement signal cannot be used. To avoid being affected by it, it is necessary to use other measurable signals instead to ensure the control effect.

Example 1

An operation control method for wind turbines under extreme wind conditions. As shown in Figure 1, the rotational speed of the wind turbine is detected in the current detection cycle. Since there are interference signals in the measurement of the rotational speed of the wind turbine, the measurement of the rotational speed of the wind turbine is performed. filter processing. Obtain the current wind turbine speed setting value, and make the difference between it and the filtered wind turbine speed to obtain the current wind turbine speed difference. Similarly, calculate the speed difference of the wind turbine at the previous moment. The difference between the current wind turbine speed and the wind turbine speed difference at the previous moment is obtained by taking the difference between the current wind turbine speed difference and the wind turbine speed difference before and after, and dividing it by the control period constant to obtain the wind turbine speed acceleration before and after. Multiplying the calculated speed acceleration of the wind turbine before and after the time and the speed difference of the wind turbine at the current moment can obtain the operating value of the differential product of the wind turbine speed difference and the speed difference.

Detect the pitch angle in the current detection cycle, look up the table between the measured pitch angle value and the preset threshold value of the wind turbine rotational speed difference and the differential product of the rotational speed difference, and perform interpolation calculation to obtain the wind power corresponding to the pitch angle at the current moment. The preset threshold value of the product of the differential product of the speed difference and the differential speed of the unit.

Determine the operating value of the wind turbine speed difference and the differential product of the speed difference and the preset threshold value of the wind turbine speed difference and the differential product of the speed difference. If the operating value is greater than the preset threshold, it means that the wind turbine is in extreme wind conditions at this moment. The operating data fluctuates violently. In order to further protect the unit, the operating state of the unit is switched to enter the power limit state, and after maintaining for 300 seconds, the unit returns to the normal operating state. If the operating value is less than the preset threshold, it means that the wind turbine has not suffered from fluctuations in operating data caused by extreme wind conditions at this moment, and the turbine can maintain normal power generation conditions.

Example 2

An operation control method for wind turbines under extreme wind conditions. By detecting the rotational speed of the wind turbines, and comparing the difference in rotational speed of the wind turbines before and after and their changes, it is judged in real time whether the wind turbines currently encounter extreme turbulent wind conditions.

details as follows:

Detect the current wind turbine speed and transmit the measurement signal to the main control system.

Due to the measurement method, signal conversion, estimation method, etc. of the wind turbine rotational speed measurement device, the directly obtained rotational speed measurement signal has interference components, which is not suitable to directly participate in the control algorithm. Therefore, low-pass filtering is performed on the currently measured rotational speed of the wind turbine to obtain the current filtered rotational speed value of the wind turbine.

Check the current wind turbine speed setting value.

Subtract the current wind turbine speed setting value from the current filtered wind turbine speed value.

Get the current wind turbine speed difference.

Detect the rotational speed of the wind turbine in the previous measurement period, and transmit the measurement signal to the main control system.

The same low-pass filtering is performed on the rotational speed of the wind turbine in the previous measurement period to obtain the filtered wind turbine rotational speed value in the previous measurement period.

Check the wind turbine speed setting value of the previous measurement period.

Subtract the wind turbine speed setting value of the previous measurement period from the filtered wind turbine speed value of the previous measurement period.

Obtain the wind turbine rotational speed difference in the previous measurement period.

Make the difference between the current wind turbine rotational speed difference and the wind turbine rotational speed difference of the previous measurement period.

Obtain the difference between the wind turbine rotational speeds before and after.

Check the control period constant.

Divide the difference between the wind turbine rotational speeds before and after by the control period constant.

Obtain the wind turbine speed acceleration before and after.

Step 2) The product of the speed acceleration of the wind turbines at the front and back moments and the speed difference of the current wind turbines is used as the operating value of the product of the speed difference and the differential product of the speed difference at the current moment.

Step 3) Detect the current pitch angle, and transmit the measured value signal of the pitch angle to the main control system.

Obtain the measured pitch angle value and interpolate it with the preset speed difference and the differential product threshold of the speed difference.

Obtain the current speed difference and the threshold value of the differential product of the speed difference.

Step 4) Judging the magnitude of the operating value of the rotational speed difference and the differential product of the rotational speed difference at the current moment and the threshold value of the differential product of the rotational speed difference and the rotational speed difference at the current moment.

If the current time speed difference and speed difference differential product operating value is less than the current time speed difference and speed difference differential product threshold, the unit's operating state remains unchanged.

If the current time speed difference and speed difference differential product operating value is greater than the current time speed difference and speed difference differential product threshold, the operating state of the unit is switched to the limited power state.

Check the current unit power setting value P1.

Set the current unit power setting value to P2 with deltaP as the slope.

When the operating state of the unit is switched (P1P2), the power-limited state starts to accumulate time t.

Determine whether the accumulated time t exceeds 300 seconds.

If it does not exceed 300 seconds, the unit power setting value is P2.

If it exceeds 300 seconds, the unit power setting value will be restored to P1.

The embodiments of the present invention provide a method for controlling the operation of a wind turbine under extreme wind conditions, which replaces the control input measurement signal of the existing scheme, thereby avoiding the difference in control effect caused by the deviation of the control input measurement. And the substitute control input measurement signals are all existing measurable signals, and there is no need to add more hardware to complete the control scheme. When the judgment condition is satisfied, the control system triggers a control action to protect the unit and reduce the load. In this embodiment, the power reduction method is adopted, but it is not limited to this method. Other control actions such as raising the minimum pitch angle can also be used.

Example 3

The process of obtaining the speed difference at the current moment in step 1) is as follows: first obtain the speed setting value of the wind turbine, then obtain the speed value of the wind turbine at the current moment, filter the speed value of the wind turbine at the current moment, and calculate the speed of the wind turbine. The difference between the speed setting value and the filter-processed speed value at the current moment is used to obtain the speed difference of the wind turbine at the current moment;

The filtering is to perform signal filtering by using a low-pass filtering method.

The calculation process of the rotational speed acceleration in step 1) is as follows: calculating the difference between the rotational speed difference of the wind turbine at the current moment and the rotational speed difference of the wind turbine at the previous moment, and obtaining the difference between the rotational speeds of the wind turbines at the previous and later times. The speed difference of the unit and the preset control period constant are calculated to obtain the speed acceleration of the wind turbine.

In step 2), the operating value of the wind turbine is obtained by multiplying the speed acceleration of the wind turbine and the speed difference of the wind turbine at the current moment.

In step 3), the triggering threshold of the control method is obtained through the following process: setting the detection period, obtaining the pitch angle of the unit within the detection period, and calculating the differential product of the rotational speed difference and the rotational speed difference of the wind turbine corresponding to the pitch angle at the current moment by using the interpolation method Preset the threshold to obtain the trigger threshold of the control method.

The preset control period in step 4) is 400s; the process of reducing the power setting value in state 2 of step 4) is performed with a slope of -150kW/s.

Example 4

The abnormality judging module interacts with the data processing module, compares the operating value of the wind turbine with a preset operating threshold, and judges the operating state of the wind turbine.

The abnormality judgment module includes operating value judgment and time judgment; the operating value judgment is used to judge the relationship between the operating value and the operating threshold, and according to the judgment result, the power setting value is given an instruction; the time judgment is used to judge the running time of the limited power state The relationship between the control cycle and the preset control cycle, and according to the judgment result, the power limit state is issued an instruction.

It should be noted that, the main control system used in the above embodiments uses the PLC controller to determine the threshold value and issue an instruction.

To sum up, the present invention designs a method to control the power operation mode of the unit through the operation state of the unit, so as to improve the operation safety of the wind turbine under extreme wind conditions. The invention innovatively adopts the rotational speed, the most reliable measurement signal of the unit, and uses the control effect and trend of the rotational speed at the current moment as a condition for judging whether the unit encounters extreme wind speed and wind direction changes, thereby entering a low load mode to protect the unit.

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention all fall within the scope of the claims of the present invention. within the scope of protection.

Claims

An operation control method for wind turbines under extreme wind conditions, characterized in that it comprises the following steps:

Step 1) Obtain the speed difference of the wind turbine at the current moment and the speed difference at the previous moment, and obtain the speed acceleration of the wind turbine;

Step 2) based on the rotational speed difference and rotational speed acceleration of step 1), obtain the operating value of the wind turbine;

Step 3) obtaining a preset trigger threshold of the wind turbine control method;

Step 4) Compare the operating value of step 2) with the trigger threshold value of step 3):

In state 1, if the operating value of the wind turbine is less than the trigger threshold, the current power setting value P1 will remain unchanged;

In state 2, if the operating value of the wind turbine is greater than the trigger threshold, the power setting value is reduced to P2. At this time, the wind turbine enters the power-limited state, and the operating time of the limited-power state is calculated. When the operating time of the limited-power state is less than or equal to the preset During the set control cycle, the power-limited state is maintained; when the running time of the power-limited state is greater than the preset control cycle, the power-limited state is terminated and the power setting value P1 is returned.
The operation control method for wind turbines under extreme wind conditions according to claim 1, characterized in that, in step 1), the process of obtaining the speed difference at the current moment is: firstly obtain the speed setting value of the wind turbine, and then obtain The rotational speed value of the wind turbine at the current moment, filter the rotational speed value of the wind turbine at the current moment, calculate the difference between the rotational speed setting value of the wind turbine and the filtered rotational speed value at the current moment, and obtain the wind turbine at the current moment. speed difference;

The acquisition process of the speed difference at the last moment is: obtain the speed value of the wind turbine at the last moment, filter the speed value of the wind turbine at the last moment, calculate the speed setting value of the wind turbine and the last moment after filtering. The difference between the speed values of , obtains the speed difference of the wind turbine at the previous moment.
The operation control method for wind turbines under extreme wind conditions according to claim 2, wherein the filtering is performed by using a low-pass filtering method for signal filtering.
The operation control method for wind turbines under extreme wind conditions according to claim 1, wherein the calculation process of the rotational speed acceleration in step 1) is: calculating the difference between the rotational speed of the wind turbine at the current moment and the wind turbine at the previous moment. The difference between the rotational speed differences is used to obtain the rotational speed difference of the wind turbine at the front and rear moments.
The operation control method for wind turbines under extreme wind conditions according to claim 1, wherein the operation value of the wind turbines in step 2) is multiplied by the speed acceleration of the wind turbines and the speed difference of the wind turbines at the current moment owned.
The operation control method for wind turbines under extreme wind conditions according to claim 1, characterized in that, in step 3), the triggering threshold of the control method is obtained through the following process: setting a detection period, and obtaining the unit's For the pitch angle, an interpolation method is used to calculate the preset threshold value of the wind turbine rotational speed difference and the differential product of the rotational speed difference corresponding to the pitch angle at the current moment, and the trigger threshold of the control method is obtained.
The operation control method for wind turbines under extreme wind conditions according to claim 1, wherein the preset control period in step 4) is 300-400s;

The process of reducing the power setting value in the state 2 of step 4) is performed with a slope of -150kW/s.
An operation control system for wind turbines under extreme wind conditions, characterized in that it includes:

The rotational speed acquisition module is used to obtain the rotational speed value of the wind turbine at the current moment and the previous moment;

The data processing module interacts with the rotational speed acquisition module. Based on the rotational speed values of the wind turbine at the current moment and the previous moment, after calculation and processing, the rotational speed difference of the wind turbine at the current moment and the rotational speed difference at the previous moment are obtained, and the rotational speed of the wind turbine is obtained. Acceleration, get the operating value of the wind turbine, and get the preset operating threshold of the wind turbine;

The abnormality judging module interacts with the data processing module, compares the operating value of the wind turbine with the trigger threshold of the preset control method of the wind turbine, and judges the operating state of the wind turbine.
The operation control system for wind turbines under extreme wind conditions according to claim 8, wherein the abnormality judgment module includes an operation value judgment and a time judgment; the operation value judgment is used for judging the difference between the operation value and the operation threshold value. The relationship between the power set value and the power setting value is issued according to the judgment result; the time judgment is used to judge the relationship between the running time of the power limit state and the preset control period, and according to the judgment result, the power limit state is issued an instruction.
The operation control system for wind turbines under extreme wind conditions according to claim 8, is characterized in that, the device that described abnormality judgment module uses is PLC controller.