KR101571492B1 - a control method for reducing wind load of a wind generator unit depended on turbulence intensity - Google Patents

Abstract

The load reduction control method of a wind power generation unit according to the present invention includes a real time wind speed measurement step of measuring a real time wind speed WS from an wind speed sensor installed in a wind power generation unit, And a driving control step of controlling the operation speed of the wind power unit to be decelerated based on a turbulence intensity (TI) derived from the turbulence intensity derivation step and a turbulence intensity deriving step for quantifying the turbulence intensity (TI) .
The standard deviation (SD) of the real-time wind speed (WS) and the average wind speed average (AVE) of the real-time wind speed measured in the real-time wind speed measuring step are calculated and the turbulence intensity (TI) is derived.

Description

A control method for reducing the load on a wind turbine generator according to the turbulence intensity is disclosed.

More particularly, the present invention relates to a load reduction control method for a wind power generation unit in accordance with a turbulence intensity for reducing a load of a wind power generation unit in a wind force with a high turbulent intensity, Control method.

Generally, in wind power plants, the presence and influence of turbulence and vibration have a significant effect on the operation and maintenance of the wind turbine generator, resulting in fatigue loads that deviate from the design values.
Typically, in the case of strong turbulence and vibration that occurs outside the design range during the operation of a wind power generation facility, there is a real problem in that a strong fatigue load occurs in a wind power generation facility not equipped with a control system and errors occur in the system.
The conventional technology can not control the wind power generation facility in real time, and the existence of the turbulence and vibration greatly influences the construction and design direction of the facility.

1 (a) is a conceptual diagram showing a wind power generation unit in a region where a turbulent flow is generated. In the case of a wind power unit installed in an area having a high turbulence intensity, there is a problem that the life of the device is shortened due to an increase in load during operation.

More specifically, a vibration occurs in a structure such as the blade 2 due to a change in load due to turbulence, and such vibration causes structural fatigue.

Also, when the turbulence intensity exceeds the design reference value in the state where the proper control is not performed, frequent errors occur, and as a result, the operation is stopped and the operation rate is lowered.

Figure 1-b shows the design criteria for the turbulence intensity according to the wind speed. For example, at the wind speed of 20m / s, the design turbulence intensity (LTI) is about 0.175. If a turbulence of about 0.25 occurs without any control under the wind speed of 20m / s wind speed, it will greatly exceed the limited turbulence intensity, resulting in strong vibration, shortening the lifetime of the wind power unit according to the fatigue load, Damage to the power plant due to errors occurs.

(Patent Document 1) JP2009-236025 A

It is an object of the present invention to provide a load reduction control method for a wind power generator unit according to a turbulence intensity that safely protects the wind power generator unit from the influence of turbulence in order to solve the above problems.

In order to achieve the above object, a load reduction control method of a wind power unit according to the present invention, which is devised to achieve the above object, includes a real time wind speed measurement step of measuring a real time wind speed WS from an wind speed sensor installed in a wind power generation unit, A turbulence intensity derivation step of quantifying the turbulence intensity TI based on the measured change of the real time wind speed WS and a turbidity intensity calculation step of calculating the turbulence intensity TI based on the turbulence intensity TI, And an operation control step of controlling the deceleration. The standard deviation (SD) of the real-time wind speed (WS) and the average wind speed average (AVE) of the real-time wind speed measured in the real-time wind speed measuring step are calculated and the turbulence intensity (TI) is derived.

The present invention has an effect of preventing the damage and shortening of the life of the wind power generating unit due to the vibration and error caused by the strong turbulence exceeding the designed value by controlling the operation speed of the wind power generating unit based on the turbulence intensity .

It is possible to cope with the turbulence intensity in real time, and thus it is possible to increase the generation amount by increasing the lifetime of the unit.

Further, it has been difficult to install a wind power generation unit when a large wake effect occurs due to a short unit arrangement distance of a land area or a complex having a high turbulent intensity. However, when the control method according to the present invention is applied, It is possible to easily select the location even in a relatively high land area, and furthermore, it is also possible to narrow the arrangement distance between the units.

1 (a) is a conceptual diagram showing a wind power generation unit in a region where a turbulent flow is generated.
Figure 1-b shows the design criteria for the turbulence intensity according to the wind speed.
2 is a conceptual diagram showing a main configuration of the wind power generation unit.
3 is a flowchart illustrating a method of controlling a load reduction of a wind power unit according to a turbulence intensity based on a turbulence intensity according to an embodiment of the present invention.
4 is a flowchart illustrating a method for controlling a load reduction of a wind power unit according to a turbulence intensity based on vibration intensity according to an embodiment of the present invention.
5 is a flowchart illustrating a control method based on turbulence intensity and vibration intensity according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating a method for controlling a load reduction of a wind power unit according to a turbulence intensity according to an embodiment of the present invention.

The load reduction control method of a wind power generation unit according to the present invention starts from a real time wind speed measurement step of measuring a real time wind speed (WS) from an wind speed sensor installed in a wind power generation unit.

Here, the wind speed sensor may be composed of various devices for measuring wind speed, and an anemometer 6 installed on the nacelle 8 of the wind power generating unit may also be considered.

When the real-time wind speed WS is measured in the real-time wind speed measurement step, a turbulence intensity deriving step for quantifying the turbulence intensity TI based on the change of the real-time wind speed WS is performed.

The turbulence intensity deriving step may include calculating a standard deviation SD of the real-time wind speed WS and an average AVE of the real-time wind speed measured in the real-time wind speed measuring step and calculating a ratio of the standard deviation SD to the average AVE The turbulence intensity (TI) is derived.

In other words, the turbulence intensity (TI) is proportional to the inverse of the average wind speed (AVE) as well as the standard deviation (SD) value indicating the degree of turbulence change. It increases as the standard deviation (SD) value increases, and decreases as the average wind speed (AVE) increases.

Here, the average (AVE) can be derived not only by arithmetic mean of the real-time wind speed (WS) measured at a predetermined time interval but also by using various filters to derive a more meaningful average value .

First, a low pass filter (low-pass filter) can be considered. After applying a low pass filter (low pass filter) to the real wind speed (WS) value, the real wind speed (WS) value over a certain value is regarded as noise and is ignored and the real wind speed And derive the average (AVE) through the arithmetic mean.

On the other hand, a moving average filter (moving average filter) may be considered. The moving average filter (moving average filter) is applied to the real-time wind speed (WS) value to ignore the real-time wind speed (WS) value before a certain time from the current time as noise and to measure the real- (WS) value as an effective range and derive the average (AVE) through the arithmetic average.

Also, in deriving the standard deviation SD, it may be considered to apply a low pass filter (low pass filter) or a moving average filter (moving average filter).

First, it is possible to consider applying a low pass filter (low-pass filter). After applying a low pass filter (low-pass filter) to the dispersion (V) value, the dispersion (V) value equal to or larger than a predetermined value is regarded as noise and neglected, And deriving the standard deviation SD based on the variance (V) value in the range.

Second, a moving average filter (moving average filter) can be considered.

The moving average filter (moving average filter) is applied to the variance (V) value, and the variance (V) value derived based on the measured real time wind speed (WS) (V) value derived on the basis of the real-time wind speed (WS) value measured within a predetermined time from the current time is regarded as an effective range, and the standard deviation (SD) is calculated based on the variance .

A standard deviation (SD) value obtained by applying a low pass filter (low pass filter) or a moving average filter (moving average filter) can be regarded as a root mean square (rms) value.

Meanwhile, it is determined whether or not to decelerate the operation speed according to the turbulence intensity (TI) derived from the turbulence intensity derivation step, and this is referred to as the operation control step.

More specifically, the step of determining whether or not the control is performed prior to the operation control step further includes the step of determining the turbulent intensity normal mode / control mode.

The turbulence intensity normal mode / control mode is determined as a control mode when the turbulence intensity TI is equal to or higher than the limited turbulence intensity LTI. When the turbulence intensity TI is less than the limited turbulence intensity LTI, And decelerates and controls the rotation speed of the blade (2) according to the operation control step only when the control mode corresponds to the control mode.

This is to ignore the turbulence intensity below a certain level in order to increase the efficiency of the control and to activate the operation control step only when a certain level of turbulence intensity (TI) is generated which may affect the lifetime of the unit.

Meanwhile, as shown in FIG. 6, the normal mode can be divided into the non-adaptive mode and the alarm mode. If the turbulence intensity (TI) is more than a predetermined value even in a normal mode where the turbulence intensity (TI) is less than the limited turbulence intensity (LTI), the alarm mode is applied to warn the wind farm operator that the danger is imminent. , The wind power generation unit is continuously operated without any control or alarm by applying the non-adaptive mode.

On the other hand, even in the above-mentioned control mode in which the turbulence intensity (TI) is equal to or higher than the limited turbulence intensity (LTI), a stop mode in which the wind turbine is stopped completely is applied when the turbulence intensity is equal to or more than a predetermined value, The rotation speed of the blade of the wind power generation unit is gradually reduced by applying the deceleration mode.

The limited turbulence intensity, which is a criterion of control or not, is one of the design criteria. As shown in FIG. 1-a, as the real-time wind speed WS decreases, the limited turbulence intensity tends to decrease as the real-time wind speed increases.

In one embodiment, an equation of the form that is inversely proportional to the real-time wind speed (WS) such as the limited turbulence intensity (LTI) = A / real wind speed (WS) + B 'can be considered. Where A and B are design constants.

On the other hand, it is possible to consider the form of an equation that is inversely proportional to the square of the real-time wind speed, such as 'LTI = A / real-time wind speed (WS) ² + B'.

The reason that the limited turbulence intensity (LTI) is inversely proportional to the real-time wind speed (WS) is that the larger the real-time wind speed, the weaker the wind power unit is from the effect of turbulence.

On the other hand, the limited turbulence intensity may be given in tabular form according to the wind speed, and may be stored and used in the wind turbine controller.

In the foregoing, the load reduction control method of the wind turbine based on the turbulence intensity has been described. In order to supplement the load reduction control method of the wind turbine based on the turbulence intensity, a control method based on the vibration strength can be performed in parallel.

4 is a flowchart illustrating a method for controlling a load reduction of a wind power unit according to a turbulence intensity based on vibration intensity according to an embodiment of the present invention.

First, the wind power generator unit is provided with a vibration sensor on one side. The term " one side " means various points within the nacelle (8) of the wind power generator, inside the blade (2)

Specifically, as shown in FIG. 4, when the vibration intensity VI measured by the vibration sensor is equal to or higher than the limiting vibration intensity LVI, it is determined as the control mode, and the vibration intensity VI) is less than the limiting vibration intensity (LVI), it is determined that the normal mode is selected, and the rotation speed of the blade (2) is controlled to be decelerated only when it corresponds to the control mode.

Meanwhile, FIG. 5 corresponds to a flowchart showing the control by the vibration intensity in parallel to complement the control method according to the turbulence intensity.

The vibration intensity normal mode / control mode determination step is a safety device for compensating for the error of the turbulence intensity normal mode / control mode determination step, wherein the turbulence intensity (TI) determined in the turbulence intensity normal mode / The speed of rotation of the blade 2 is decelerated when the vibration intensity VI is judged to be equal to or higher than the limiting vibration intensity VLI even when it is judged that the vibration intensity is less than the limit vibration intensity LTI.

On the other hand, the vibration intensity VI may simply mean the magnitude or amplitude of the real-time vibration, and the limiting vibration intensity LVI may be considered to limit the amplitude more than a certain level.

On the other hand, deriving in a manner similar to the limited turbulence intensity (LTI) can also be considered. That is, the real-time vibration (RV) is measured, and the vibration intensity (VI) is determined using the average value and the standard deviation. The limiting vibration intensity LVI is in a form inversely proportional to the size of the real-time vibration RV including the constants C and D defined in the design, such as 'limited vibration intensity LVI = C / real-time vibration RV + D' Can be considered.

On the other hand, we can consider the form of the form of the inverse proportion to the square of the real-time vibration (RV) magnitude, cubic, such as the limiting vibration intensity (LVI) = C / real vibration (RV) ² + D '.

On the other hand, an expression of the form that is inversely proportional to the real-time wind speed such as the limiting vibration intensity (LVI) = C / the real time wind speed (WS) + D 'can be considered. In this case, as the real-time wind speed WS is increased, the LTI value is set to a lower limit, so that operation instability due to vibration during high-speed rotation can be prevented in advance.

Meanwhile, in the final stage, the operation control step is a step of decelerating or stopping the rotation speed of the blade 2 when the control mode corresponds to the deceleration mode or the stop mode.

Hereinafter, a method of decelerating the rotational speed of the blade 2 will be described.

The output of the wind power generation unit has a correlation such as: output (P) = rotational force (torque) X revolutions per hour (blade rotational speed).

To reduce the rotational speed of the blade, i) the output P increases the torque (torque) at a certain prespecified condition, ii) the output P decreases at a certain constant generator torque (torque), iii) And increasing the rotational force (torque) and reducing the output.

First, in the case of i), the rotor load of the generator is increased and the generator rotational torque (torque) is increased as a result of maintaining the total output P, i.e., maintaining the blade pitch angle, , It may be considered to reduce the rotational speed of the blade.

In the case of ii), the pitch angle is controlled while maintaining the generator load (torque) by maintaining the rotor load of the generator, and as a result, the output (P) is decreased to reduce the rotational speed of the blades.

Finally, in case iii), the load on the generator rotor is increased to increase the generator rotational torque (torque) while adjusting the blade pitch angle to reduce the output, thereby weighting the reduction in the blade rotational speed.

In addition to i) to iii), it is also conceivable to further reduce the rotational speed of the blade 2 through a hub brake which is provided between the hub 1 and the nacelle 8 and fixed to each other, And v) a shaft 3 which is provided between the hub 1 and the generator 5 and decelerates the shaft 3 that transmits the rotational force of the blade 2 to the generator 5, It may be considered to further decelerate the rotation speed.

Furthermore, iv) and v) serve to completely stop the blade in the stop mode. Of course, even if it is determined that the engine is in the stop mode, the blades are decelerated in i) to v) like the deceleration mode, and iv) and v) are completely stopped when the rotational speed of the blades is less than a predetermined value.

On the other hand, if the turbulence intensity (TI) is again determined to be about the normal mode or the deceleration mode even in the process of deciding the stop mode and stopping for the purpose of stopping, the mode is shifted from the stop mode to the normal mode or the deceleration mode.

Further, when the turbulence intensity (TI) deviates from the degree corresponding to the stop mode in the fully stopped state, it is restarted.

More broadly, each of the steps described above is repeatedly performed at predetermined time intervals. The above-described real-time wind speed measurement step is repeated infinitely at predetermined time intervals after the operation control step according to the control mode. If the normal mode is determined through the turbulence intensity derivation step and the normal mode / control mode determination step, , I.e., decelerating or stopping control, the rotation of the blade is accelerated again at the rotational speed corresponding to the real-time wind speed.

Unless otherwise defined, all terms used herein, including technical or scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, unless explicitly defined in the present application, it should not be interpreted as an ideal or overly formal sense.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, You should see.

1: Hub
2: blade
3: Shaft
4: Gearbox
5: generator
6: Anemometer
7: weather vane
8: Nacelle
9: Towers
WS: Real-time wind velocity
SD: standard deviation
V: dispersion
AVE: Average
TI: turbulent intensity
LTI: Limited turbulence intensity
RV: Real-time vibration
VI: Vibration strength
LVI: Limited vibration strength
A, B, C, D: design constants

Claims (14)

A real-time wind speed measuring step of measuring a real-time wind speed (WS) from an wind speed sensor installed in the wind power generation unit, and
A turbulence intensity derivation step of quantifying a turbulence intensity (TI) based on a change in the real-time wind speed (WS) measured in the real-time wind speed measurement step;
An operation control step of controlling the operation speed of the wind turbine unit to be decelerated based on the turbulence intensity (TI) derived from the turbulence intensity deriving step;
If the turbulence intensity (TI) is equal to or higher than the limited turbulence intensity (LTI), the control mode is determined.
When the turbulence intensity TI is less than the limited turbulence intensity LTI,
The turbulence intensity normal mode / control mode determination step of performing the control to decelerate or stop the rotation speed of the blade (2) only in the case of the control mode.
The wind power generation unit is provided with a vibration sensor on one side,
When the vibration intensity VI measured by the vibration sensor is equal to or greater than the limiting vibration intensity LVI, and when the vibration intensity VI measured by the vibration sensor is less than the limiting vibration intensity LVI Determining whether the blade is in a normal mode and performing control to decelerate or stop the rotation speed of the blade only when the mode corresponds to the control mode,
The vibration intensity normal mode / control mode determination step may further include determining the vibration intensity normal mode / control mode based on the vibration intensity VI, even when the turbulence intensity TI determined in the turbulence intensity normal mode / control mode determination step is less than the limiting vibration intensity LTI. Includes decelerating or stopping the rotation speed of the blade (2) when it is judged to be equal to or higher than the limiting vibration intensity (VLI)
The normal mode includes an alarm mode in which an alarm is sounded or displayed when a turbulence intensity (TI) is equal to or more than a predetermined value, and a silent mode in which additional control is not performed when the turbulence intensity (TI) In addition,
Wherein the control mode includes a stop mode for completely stopping the rotation of the blade when the turbulence intensity is equal to or more than a predetermined value and a deceleration mode for decelerating the rotation speed of the blade when the turbulence intensity is equal to or lower than the predetermined value,
The limited turbulence intensity increases as the real-time wind speed WS decreases, and decreases as the real-time wind speed increases. The limited turbulence intensity includes a formula of 'limited turbulence intensity (LTI) = A / real wind speed (WS) + B' Control Method of Load Reduction of Wind Power Generation Unit according to Turbulent Intensity. The method according to claim 1,
The turbulence intensity deriving step derives the standard deviation SD of the real-time wind speed WS and the average AVE of the real-time wind speed WS measured in the real-time wind speed measuring step, (TI) is derived as a ratio of the air-fuel ratio (AVE) of the turbine. 3. The method of claim 2,
The average (AVE)
Wherein the controller is derived by applying a low-pass filter or a moving average filter to the real-time wind speed (WS) value. 3. The method of claim 2,
The standard deviation (SD)
Wherein a value of a dispersion (V) of the real-time wind speed (WS) is derived by applying a low-pass filter or a moving average filter. Reduction control method. The method according to claim 1,
Wherein the wind speed sensor includes an anemometer (6) installed on an upper portion of a nacelle (8) of a wind power generator unit. delete delete delete delete delete The method according to claim 1,
Wherein the operation control step decelerates the rotational speed of the e blade (2) by adjusting the pitch of the blade (2) to reduce the output (P). The turbine generator according to claim 1, characterized in that the rotational speed of the blade (2) is reduced by increasing the load of the rotor (5) of the generator (5) Of the load. 13. The method according to claim 11 or 12,
The operation control step further reduces or stops the rotation speed of the blade (2) through a hub brake which is provided between the hub (1) and the frame of the nacelle (8) and fixes them to each other. Wherein the load reduction control method is applied to the wind power generation unit. 13. The method according to claim 11 or 12,
The operation control step includes controlling the rotation speed of the blade 2 through the shaft brake which is provided between the hub 1 and the generator 5 and decelerates the shaft 3 that transmits the rotational force of the blade 2 to the generator 5, Wherein the control unit decelerates or stops the wind turbine.

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