CN112149363A - Two-dimensional Jensen model and double-beam laser radar-based wake region fan power prediction method - Google Patents

Abstract

The invention discloses a wake flow area fan power prediction method based on a two-dimensional Jensen model and a double-beam laser radar, which comprises the steps of calculating the wake flow radius of the cross section position of a radar wind measuring point of a downstream fan and the wake flow radius of the cross section position of a wind wheel plane of the downstream fan; judging whether the downstream fan is positioned on the left side or the right side of the wake central axis according to the included angle between the connecting line of the upstream fan and the downstream fan and the wake central axis of the upstream fan; calculating wind speed values measured by the compensated radar left and right wind measuring points of the downstream fan and a yaw error angle of the compensated downstream fan according to the position of the radar wind measuring point in the wind speed area; calculating the equivalent inflow wind speed of the downstream fan according to the position of the wind wheel plane of the downstream fan in the wake flow area; and calculating the power output value of the downstream fan. The invention also discloses a corresponding prediction system. The method can accurately calculate the power output value of the downstream fan with the yaw error in the wake flow area.

Description

Power prediction of wind turbines in wake region based on two-dimensional Jensen model and dual-beam lidar test method

technical field

The invention belongs to the technical field of fan control, and in particular relates to a method for predicting the power of a fan in a wake region based on a two-dimensional Jensen model and a double-beam laser radar.

Background technique

As a kind of abundant and clean new energy, wind energy is one of the most promising renewable energy sources in the world. With the increase of grid transmission and accommodation capacity, wind farm owners pay more attention to the improvement of wind turbine power generation efficiency. The wake of the upstream fan will significantly reduce the power output of the downstream fan. Therefore, the accurate calculation of the power output value of the downstream fan in the upstream fan wake area is important for the control optimization of the fans in the wind farm and improving the overall power generation efficiency of the wind farm. significance. At present, there are existing fan power calculation methods considering wake flow. However, due to the influence of the yaw error angle of the upstream and downstream fans, this method is inaccurate in judging the position of the wake region where the downstream fans are located, and the calculated power output value when the downstream fans are in the wake region is not accurate.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a method for predicting the power of a fan in the wake region based on a two-dimensional Jensen model and a double-beam laser radar.

The technical solution for realizing the purpose of the present invention is: a method for predicting the power of a blower fan in the wake region based on a two-dimensional Jensen model and a double-beam laser radar. The specific steps are as follows:

Step 1: Collect the inflow wind speed and inflow wind direction of the upstream fan, collect the yaw error angle of the upstream fan, collect the wind speed value measured by the left and right wind measuring points of the double-beam lidar of the downstream fan, and determine the distance between the fans in the wind farm. azimuth angle;

Step 2, according to the two-dimensional Jensen model and the spacing and azimuth angle between the fans, calculate the wake radius of the section where the radar wind measuring point of the downstream fan is located, and the wake radius of the section where the downstream fan rotor plane is located;

Step 3: Determine whether the two wind measurement points of the downstream wind turbine radar are both in the natural wind speed area, whether one wind measurement point is in the wake area and the other wind measurement point is in the natural wind speed area, or both wind measurement points are in the natural wind speed area. wake area;

Step 4: According to the angle between the connection line of the upstream and downstream fans and the central axis of the wake of the upstream fan, determine whether the downstream fan is on the left or the right of the central axis of the wake;

Step 5, according to the position of the radar wind measurement point in the wind speed area, calculate the wind speed value measured by the left and right wind measurement points of the downstream wind turbine after compensation and the yaw error angle of the downstream wind turbine after compensation;

Step 6, determine whether the plane of the downstream fan rotor is completely in the natural wind speed region, partially in the wake region, or completely in the wake region;

Step 7: Calculate the equivalent inflow wind speed of the downstream fan according to the position of the wind wheel plane of the downstream fan in the wake region;

Step 8: Calculate the power output value of the downstream fan.

Further, in step 1, the inflow wind speed and inflow wind direction of the upstream fan are collected by the SCADA system of the fan, the yaw error angle is collected by the double beam lidar installed above the nacelle of the upstream fan, and the yaw error angle is collected by using the double beam installed above the nacelle of the downstream fan. The lidar collects the wind speed values measured by the left and right wind measuring points, and determines the spacing and azimuth angle between the fans in the wind farm according to the construction site selection of the wind farm.

Further, in step 2, according to the two-dimensional Jensen model and the distribution distance and distribution angle of the fan, the wake radius at the cross-sectional position where the radar wind measurement point of the downstream fan is located, and the wake at the cross-sectional position where the downstream fan rotor plane is located are calculated respectively. Radius, the specific method is:

Define the angle θ _L between the connection line of the upstream and downstream fans and the center axis of the wake of the upstream fan as:

θ _L = 0.3C _T ·β ₁ +θ _FWT -θ _x

In the formula, θ _x is the inflow wind direction angle, θ _FWT is the azimuth angle of the upstream fan relative to the downstream fan, β ₁ is the yaw error angle of the upstream fan, and C _T is the fan lift coefficient;

Define the vertical distance between the section where the radar wind measurement point of the downstream fan is located and the upstream fan as L _l , and the calculation formula is:

L _l =Ldcos(θ _L )-z ₀ cos(α)

In the formula, Ld is the distance between the nacelles of the upstream and downstream fans, z ₀ is the distance between the radar wind measurement point of the downstream fan and the radar, and α is the angle between the radar laser beam of the downstream fan and the central axis of the downstream fan;

Then the formula for calculating the wake radius at the cross-section position where the radar wind measuring point of the downstream fan is located is:

R _l =kL _l +r ₀

In the formula, k is the wake attenuation coefficient, and r ₀ is the rotor radius of the fan.

Define the vertical distance between the section where the rotor plane of the downstream fan is located and the upstream fan as L _w , the calculation formula is:

L _w =Ldcos(θ _L )

Then the formula for calculating the wake radius at the cross-sectional position where the wind wheel plane of the downstream fan is located is:

R _w =kL _w +r ₀

Further, in step 3, it is determined whether the two wind measurement points of the downstream fan radar are both in the natural wind speed area, whether one wind measurement point is in the wake area and the other wind measurement point is in the natural wind speed area, or whether the two wind measurement points are in the natural wind speed area. The wind points are all in the wake region, and the specific methods are as follows:

If Ldsin(θ _L )-z ₀ sin(α)>R _l , the two wind measurement points of the downstream wind turbine radar are in the natural wind speed area;

If Ldsin(θ _L )-z ₀ sin(α)≤R _l &Ldsin(θ _L )+z ₀ sin(α)>R _l , then one wind measurement point of the downstream wind turbine radar is in the wake region, and the other The wind measuring point is in the natural wind speed area;

If Ldsin(θ _L )-z ₀ sin(α)≤R _l &Ldsin(θ _L )+z ₀ sin(α)≤R _l , then the two wind measurement points of the downstream wind turbine radar are both in the wake region;

Among them, Ld is the distance between the nacelles of the upstream and downstream fans, θ _L is the angle between the upstream and downstream fans and the center axis of the upstream fan wake, z ₀ is the distance between the radar wind measurement point of the downstream fan and the radar, α is the downstream fan The angle between the radar laser beam and the central axis of the downstream fan, R _l is the wake radius of the cross-section where the radar wind measurement point of the downstream fan is located.

Further, in step 4, according to the angle between the connection line of the upstream and downstream fans and the central axis of the wake of the upstream fan, it is determined whether the downstream fan is on the left or the right of the central axis of the wake, and the specific method is as follows:

If the angle between the connecting line of the upstream and downstream fans and the central axis of the wake of the upstream fan is less than 0, the downstream fan is on the left side of the central axis of the wake, otherwise it is on the right side of the central axis of the wake.

Further, in step 5, according to the position of the radar wind measuring point in the wind speed area, calculate the wind speed value measured by the left and right wind measuring points of the downstream fan after compensation and the yaw error angle of the downstream fan after compensation, and the specific method is: :

(1) If the downstream fan is on the left side of the center axis of the wake, and the left wind measurement point of the radar is in the natural wind speed area and the right wind measurement point is in the wake area, the wind speed compensation coefficient of the right wind measurement point is:

where C _T is the lift coefficient of the fan, k is the wake attenuation coefficient, r ₀ is the radius of the fan rotor, and L _l is the vertical distance between the section where the radar wind measurement point of the downstream fan is located and the upstream fan;

r _rk is the vertical distance between the position of the right wind measurement point and the center line of the wake plane, and the calculation formula is:

r _rk =Ldsin(θ _L )-z ₀ sin(α)

In the formula, Ld is the distance between the nacelles of the upstream and downstream fans, θ _L is the angle between the upstream and downstream fan lines and the center axis of the upstream fan wake, z ₀ is the distance between the radar wind measurement point of the downstream fan and the radar, and α is the downstream The angle between the fan radar laser beam and the central axis of the downstream fan;

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1

V _b =V _los2 /C _rw

In the formula, V _los1 and V _los2 are the actual measured wind speed values of the left and right wind measuring points of the downstream wind turbine radar respectively;

(2) If the downstream fan is on the right side of the wake center axis, and the left wind measurement point of the radar is in the wake area and the right wind measurement point is in the natural wind speed area, the wind speed compensation coefficient of the left wind measurement point is:

r _lk is the vertical distance between the position of the left wind measurement point and the center line of the wake plane, and the calculation formula is:

r _lk =Ldsin(θ _L )-z ₀ sin(α)

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2

(3) If the downstream fan is on the left side of the center axis of the wake and the left and right wind measuring points of the radar are in the wake region, the wind speed compensation coefficients of the left and right wind measuring points are:

r _lk and r _rk are the vertical distances between the positions of the left and right wind measurement points and the center line of the wake plane, respectively. The calculation formula is:

r _lk =Ldsin(θ _L )+z ₀ sin(α)

r _rk =|Ldsin(θ _L )-z ₀ sin(α)|

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2 /C _rw

(4) If the downstream fan is on the right side of the center axis of the wake and the left and right wind measuring points of the radar are in the wake region, the wind speed compensation coefficients of the left and right wind measuring points are:

r _lk and r _rk are the vertical distances between the positions of the left and right wind measurement points and the center line of the wake plane, respectively. The calculation formula is:

r _lk =|Ldsin(θ _L )-z ₀ sin(α)|

r _rk =Ldsin(θ _L )+z ₀ sin(α)

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2 /C _rw

(5) If the left and right wind measurement points of the downstream fan radar are in the natural wind speed area, the wind speed measured by the left and right wind measurement points of the downstream fan radar after compensation is:

V _a =V _los1

V _b =V _los2

According to the different wind speed areas of the downstream fans, the yaw error angle of the downstream fans after compensation is calculated. The specific formula is:

Further, in step 6, it is judged whether the plane of the wind wheel of the downstream fan is completely in the natural wind speed area, partly in the wake area, or completely in the wake area, and the specific method is as follows:

If Ldsin(θ _L )-r ₁ >R _w , the plane of the downstream fan rotor is completely in the natural wind speed region;

If Ldsin(θ _L )-r ₁ ≤R _w &Ldsin(θ _L )+r ₁ >R _w , the plane part of the downstream fan rotor is in the wake region;

If Ldsin(θ _L )-r ₁ ≤R _w &Ldsin(θ _L )+r ₁ ≤R _w , the plane of the downstream fan rotor is completely in the wake region;

Among them, r ₁ is the projected length of the rotor radius on the vertical wake centerline, and the calculation formula is:

r ₁ =r ₀ cos( _0.3CT ·β ₁ +β ₂ )

Among them, Ld is the distance between the nacelles of the upstream and downstream fans, θ _L is the angle between the upstream and downstream fan lines and the central axis of the wake of the upstream fan, R _w is the wake radius at the cross-sectional position of the plane of the downstream fan's rotor, r ₀ is the radius of the fan rotor, β ₁ is the yaw error angle of the upstream fan, β ₂ is the yaw error angle of the downstream fan after compensation, and C _T is the lift coefficient of the fan.

Further, according to the position of the downstream fan rotor plane in the wake region, calculate the equivalent inflow wind speed of the downstream fan, and the specific method is as follows:

(1) If the plane of the downstream fan rotor is completely in the natural wind speed zone, the equivalent inflow wind speed of the downstream fan is:

Among them, u ₀ is the inflow wind speed of the upstream fan.

(2) If the plane part of the downstream fan rotor is in the wake area, the area of the downstream fan rotor plane in the wake area is:

Among them, R _w is the wake radius of the cross-sectional position of the downstream fan rotor plane, and r ₁ is the projected length of the rotor radius on the vertical wake centerline;

Let O ₁ , O ₂ be the wake center at the plane of the downstream fan rotor and the center of the downstream fan rotor, B be any intersection point between the edge of the wake region at the plane of the downstream fan rotor and the edge of the downstream fan rotor, θ ₁ is the included angle between the connecting line O ₁ O ₂ and the connecting line O ₁ B, and θ ₂ is the included angle between the connecting line O ₁ O ₂ and the connecting line O ₂ B, and the calculation formula is:

Among them, _LR is the vertical distance from the center of the downstream fan to the centerline of the wake of the upstream fan:

L _R =Ldsin(θ _L )

Among them, Ld is the distance between the nacelles of the upstream and downstream fans, and θ _L is the angle between the upstream and downstream fan lines and the central axis of the upstream fan wake;

The area of the downstream fan rotor is:

S=πr ₀ ²

Among them, r ₀ is the radius of the rotor.

The projected area of the wind rotor on the vertical wake centerline is:

S ₁ =πr ₁ ²

Among them, r ₁ is the projected length of the rotor radius on the vertical wake centerline;

The formula for calculating the wind speed _ur in the wake region is:

In the formula, C _T is the lift coefficient of the fan, k is the wake attenuation coefficient, r ₀ is the rotor radius of the fan, L _w is the vertical distance between the section where the plane of the fan rotor of the downstream fan is located and the upstream fan, and r is any point on the plane of the fan rotor The vertical distance from the centerline of the wake plane, u ₀ is the inflow wind speed of the upstream fan;

The formula for calculating the equivalent inflow wind speed of the downstream fan is:

Among them, a and b are the upper and lower limits of the integral, and the values are:

a=L _R -r ₁

b= _Rw

(3) If the plane part of the rotor of the downstream fan is in the wake region, the calculation formula of the equivalent inflow wind speed of the downstream fan is:

in,

a=L _R -r ₁

b=L _R +r ₁

Further, in step 8, the power output value of the downstream fan is calculated, and the specific formula is:

为下游风机等效入流风速，β₂为补偿后的下游风机偏航误差角度。Among them, ρ is the air density, S is the rotor area of the downstream fan, C _p is the power utilization coefficient of the downstream fan,

is the equivalent inflow wind speed of the downstream fan, and β ₂ is the yaw error angle of the downstream fan after compensation.

A wake region fan power prediction system based on two-dimensional Jensen model and double-beam lidar, including:

The data acquisition module is used to collect the inflow wind speed and inflow wind direction of the upstream fan, collect the yaw error angle of the upstream fan, and collect the wind speed value measured by the left and right wind measuring points of the double-beam lidar of the downstream fan, and determine the distance between the fans in the wind farm. spacing and azimuth angle;

The wake radius calculation module is used to calculate the wake radius at the cross-sectional position where the radar wind measurement point of the downstream fan is located, and the cross-sectional position of the downstream fan rotor plane according to the two-dimensional Jensen model and the distance and azimuth angle between the fans. wake radius;

The wind measurement point position judgment module is used to judge whether the two wind measurement points of the downstream wind turbine radar are both in the natural wind speed area, whether one wind measurement point is in the wake area and the other wind measurement point is in the natural wind speed area, or whether the two wind measurement points are in the natural wind speed area. The wind measurement points are all in the wake region;

The fan position judgment module is used to judge whether the downstream fan is on the left or right side of the wake center axis according to the angle between the connection line of the upstream and downstream fans and the center axis of the wake flow of the upstream fan;

The compensation module is used to calculate the wind speed value measured by the left and right wind measuring points of the downstream fan after compensation and the yaw error angle of the downstream fan after compensation according to the position of the radar wind measuring point in the wind speed area;

The wind rotor plane position judgment module is used to judge whether the wind rotor plane of the downstream fan is completely in the natural wind speed area, partly in the wake area, or completely in the wake area;

The equivalent inflow wind speed calculation module is used to calculate the equivalent inflow wind speed of the downstream fan according to the position of the downstream fan rotor plane in the wake region;

The power output calculation module is used to calculate the power output value of the downstream fan.

Compared with the prior art, the present invention has the significant advantages that: based on the two-dimensional Jensen model, combined with the change of the yaw error angle of the upstream fan to the position of the wake region, the yaw of the downstream fan after compensation in the wake region is accurately calculated Error angle, and based on this, the equivalent inflow wind speed of the downstream fans in the wake region of the upstream fan is calculated, and finally the accurate calculation of the power output value of the downstream fan wake region is realized, which is the control optimization of wake suppression in the wind farm. Lay the foundation.

Description of drawings

FIG. 1 is a flow chart of a method for predicting the power of a fan in the wake region based on a two-dimensional Jensen model and a dual-beam lidar according to the present invention.

Figure 2 is a schematic diagram of the structure of a dual-beam lidar.

FIG. 3 is a schematic diagram of the present invention for judging the wind speed zone where the plane of the downstream fan rotor is located.

4 is a schematic diagram of calculating the area of the downstream fan rotor plane in the wake region according to the present invention.

FIG. 5 is a yaw error angle diagram of the downstream fan after compensation according to the present invention.

FIG. 6 is a comparison diagram of the power output value in the wake region of the downstream fan predicted by the present invention and the actual power output value.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

As shown in Figure 1, based on the two-dimensional Jensen model and dual-beam lidar fan power prediction method in the wake region, the specific steps are as follows:

Step 1: Collect the inflow wind speed and inflow wind direction of the upstream fan, collect the yaw error angle of the upstream fan, collect the wind speed value measured by the left and right wind measuring points of the double-beam lidar of the downstream fan, and determine the distance between the fans in the wind farm. azimuth angle;

The inflow wind speed and inflow wind direction of the upstream fan are collected by the SCADA system of the fan, the yaw error angle is collected by the double-beam lidar installed above the nacelle of the upstream fan (as shown in Figure 2), and the yaw error angle is collected by using the double beam installed above the nacelle of the downstream fan. The lidar (as shown in Figure 2) collects the wind speed values measured by the left and right wind measuring points, and determines the distance and azimuth angle between the fans in the wind farm according to the construction site selection of the wind farm.

Step 2, according to the two-dimensional Jensen model and the distribution distance and distribution angle of the fan, calculate the wake radius at the cross-sectional position where the radar wind measuring point of the downstream fan is located, and calculate the wake radius at the cross-sectional position where the downstream fan rotor plane is located;

Define the angle θ _L between the connection line of the upstream and downstream fans and the center axis of the wake of the upstream fan as:

θ _L = 0.3C _T ·β ₁ +θ _FWT -θ _x

In the formula, θ _x is the inflow wind direction angle, θ _FWT is the azimuth angle of the upstream fan relative to the downstream fan, β ₁ is the yaw error angle of the upstream fan, and C _T is the fan lift coefficient;

Define the vertical distance between the section where the radar wind measurement point of the downstream fan is located and the upstream fan as L _l , and the calculation formula is:

L _l =Ldcos(θ _L )-z ₀ cos(α)

In the formula, Ld is the distance between the nacelles of the upstream and downstream fans, z ₀ is the distance between the radar wind measurement point of the downstream fan and the radar, and α is the angle between the radar laser beam of the downstream fan and the central axis of the downstream fan;

Then the formula for calculating the wake radius at the cross-section position of the radar wind measurement point is:

R _l =kL _l +r ₀

In the formula, k is the wake attenuation coefficient, and r ₀ is the rotor radius of the fan.

Define the vertical distance between the section where the rotor plane of the downstream fan is located and the upstream fan as L _w , the calculation formula is:

L _w =Ldcos(θ _L )

Then the formula for calculating the wake radius at the cross-sectional position where the wind wheel plane of the downstream fan is located is:

R _w =kL _w +r ₀

Step 3: Determine whether the two wind measurement points of the downstream wind turbine radar are both in the natural wind speed area, whether one wind measurement point is in the wake area and the other wind measurement point is in the natural wind speed area, or both wind measurement points are in the natural wind speed area. wake area;

If Ldsin(θ _L )-z ₀ sin(α)>R _l , the two wind measurement points of the downstream wind turbine radar are in the natural wind speed area;

If Ldsin(θ _L )-z ₀ sin(α)≤R _l &Ldsin(θ _L )+z ₀ sin(α)>R _l , then one wind measurement point of the downstream wind turbine radar is in the wake region, and the other The wind measuring point is in the natural wind speed area;

If Ldsin(θ _L )-z ₀ sin(α)≤R _l &Ldsin(θ _L )+z ₀ sin(α)≤R _l , then the two wind measurement points of the downstream wind turbine radar are both in the wake region;

Step 4: According to the angle between the connection line of the upstream and downstream fans and the central axis of the wake of the upstream fan, determine whether the downstream fan is on the left or the right of the central axis of the wake;

If the angle between the connecting line of the upstream and downstream fans and the central axis of the wake of the upstream fan is less than 0, the downstream fan is on the left side of the central axis of the wake, otherwise it is on the right side of the central axis of the wake.

Step 5, according to the position of the radar wind measurement point in the wind speed area, calculate the wind speed value measured by the left and right wind measurement points of the downstream wind turbine radar after compensation, and the yaw error angle of the downstream wind turbine after compensation;

According to the position of the radar wind measuring point in the wind speed area, the wind speed values measured by the left and right wind measuring points of the downstream wind turbine after calculation and compensation are divided into five specific situations:

(1) If the downstream fan is on the left side of the center axis of the wake, and the left wind measurement point of the radar is in the natural wind speed area and the right wind measurement point is in the wake area, the wind speed compensation coefficient of the right wind measurement point is:

In the formula, C _T is the lift coefficient of the fan;

r _rk is the vertical distance between the position of the right wind measurement point and the center line of the wake plane, and the calculation formula is:

r _rk =Ldsin(θ _L )-z ₀ sin(α)

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1

V _b =V _los2 /C _rw

In the formula, V _los1 and V _los2 are the actual measured wind speed values of the left and right wind measuring points of the downstream wind turbine radar respectively;

(2) If the downstream fan is on the right side of the wake center axis, and the left wind measurement point of the radar is in the wake area and the right wind measurement point is in the natural wind speed area, the wind speed compensation coefficient of the left wind measurement point is:

In the formula, r _lk is the vertical distance between the position of the left wind measurement point and the center line of the wake plane, and the calculation formula is:

r _lk =Ldsin(θ _L )-z ₀ sin(α)

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2

(3) If the downstream fan is on the left side of the center axis of the wake and the left and right wind measuring points of the radar are in the wake region, the wind speed compensation coefficients of the left and right wind measuring points are:

where r _lk and r _rk are the vertical distances between the positions of the left and right wind measurement points and the centerline of the wake plane, respectively. The calculation formula is:

r _lk =Ldsin(θ _L )+z ₀ sin(α)

r _rk =|Ldsin(θ _L )-z ₀ sin(α)|

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2 /C _rw

(4) If the downstream fan is on the right side of the center axis of the wake and the left and right wind measuring points of the radar are in the wake region, the wind speed compensation coefficients of the left and right wind measuring points are:

where r _lk and r _rk are the vertical distances between the positions of the left and right wind measurement points and the centerline of the wake plane, respectively. The calculation formula is:

r _lk =|Ldsin(θ _L )-z ₀ sin(α)|

r _rk =Ldsin(θ _L )+z ₀ sin(α)

The wind speed values measured by the left and right wind measuring points of the downstream wind turbine radar after compensation are:

V _a =V _los1 /C _lw

V _b =V _los2 /C _rw

(5) If the left and right wind measurement points of the downstream fan radar are in the natural wind speed area, the wind speed measured by the left and right wind measurement points of the downstream fan radar after compensation is:

V _a =V _los1

V _b =V _los2

According to the different wind speed areas of the downstream fans, the yaw error angle of the downstream fans after compensation is calculated. The specific formula is:

Step 6, determine whether the plane of the downstream fan rotor is completely in the natural wind speed region, partially in the wake region, or completely in the wake region, the schematic diagram is shown in Figure 3;

If Ldsin(θ _L )-r ₁ >R _w , the plane of the downstream fan rotor is completely in the natural wind speed region;

If Ldsin(θ _L )-r ₁ ≤R _w &Ldsin(θ _L )+r ₁ >R _w , the plane part of the downstream fan rotor is in the wake region;

If Ldsin(θ _L )-r ₁ ≤R _w &Ldsin(θ _L )+r ₁ ≤R _w , the plane of the downstream fan rotor is completely in the wake region;

Among them, r ₁ is the projected length of the rotor radius on the vertical wake centerline, and the calculation formula is:

r ₁ =r ₀ cos( _0.3CT ·β ₁ +β ₂ )

Step 7: Calculate the equivalent inflow wind speed of the downstream fan according to the difference between the plane of the downstream fan's rotor in the wake region;

According to the position of the downstream fan rotor plane in the wake region, there are three specific situations:

(1) If the plane of the downstream fan rotor is completely in the natural wind speed zone, the equivalent inflow wind speed of the downstream fan is:

Among them, u ₀ is the inflow wind speed of the upstream fan.

(2) If the plane part of the downstream fan rotor is in the wake area, the area of the downstream fan rotor plane in the wake area is:

As shown in Figure 4, let O ₁ and O ₂ be the wake center at the plane of the downstream fan rotor and the center of the downstream fan rotor, and B be the distance between the edge of the wake region at the plane of the downstream fan rotor and the edge of the downstream fan rotor For any intersection, θ ₁ is the angle between the line O ₁ O ₂ and the line O ₁ B, and θ ₂ is the angle between the line O ₁ O ₂ and the line O ₂ B. The calculation formula is:

Among them, _LR is the vertical distance from the center of the downstream fan to the centerline of the wake of the upstream fan:

L _R =Ldsin(θ _L )

The area of the downstream fan rotor is:

S=πr ₀ ²

The projected area of the wind rotor on the vertical wake centerline is:

S ₁ =πr ₁ ²

The formula for calculating the wind speed _ur in the wake region is:

The formula for calculating the equivalent inflow wind speed of the downstream fan is:

Among them, a and b are the upper and lower limits of the integral, and the values are:

a=L _R -r ₁

b= _Rw

(3) If the plane part of the rotor of the downstream fan is in the wake region, the calculation formula of the equivalent inflow wind speed of the downstream fan is:

in,

a=L _R -r ₁

b=L _R +r ₁

Step 8, calculate the power output value of the downstream fan;

The calculation formula is:

The present invention also proposes a wake region fan power prediction system based on the two-dimensional Jensen model and the double-beam laser radar, including:

The data acquisition module is used to collect the inflow wind speed and inflow wind direction of the upstream fan, collect the yaw error angle of the upstream fan, and collect the wind speed value measured by the left and right wind measuring points of the double-beam lidar of the downstream fan, and determine the distance between the fans in the wind farm. spacing and azimuth angle;

The wake radius calculation module is used to calculate the wake radius at the cross-sectional position where the radar wind measurement point of the downstream fan is located, and the cross-sectional position of the downstream fan rotor plane according to the two-dimensional Jensen model and the distance and azimuth angle between the fans. wake radius;

The wind measurement point position judgment module is used to judge whether the two wind measurement points of the downstream wind turbine radar are both in the natural wind speed area, whether one wind measurement point is in the wake area and the other wind measurement point is in the natural wind speed area, or whether the two wind measurement points are in the natural wind speed area. The wind measurement points are all in the wake region;

The fan position judgment module is used to judge whether the downstream fan is on the left or right side of the wake center axis according to the angle between the connection line of the upstream and downstream fans and the center axis of the wake flow of the upstream fan;

The compensation module is used to calculate the wind speed value measured by the left and right wind measuring points of the downstream fan after compensation and the yaw error angle of the downstream fan after compensation according to the position of the radar wind measuring point in the wind speed area;

The wind rotor plane position judgment module is used to judge whether the wind rotor plane of the downstream fan is completely in the natural wind speed area, partly in the wake area, or completely in the wake area;

The equivalent inflow wind speed calculation module is used to calculate the equivalent inflow wind speed of the downstream fan according to the position of the downstream fan rotor plane in the wake region;

The power output calculation module is used to calculate the power output value of the downstream fan.

A computer device, comprising a memory, a processor, and a computer program stored on the memory and running on the processor, the processor implements a wake based on a two-dimensional Jensen model and a dual-beam lidar when the processor executes the computer program District fan power prediction.

A computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, realizes power prediction of a wake region fan based on a two-dimensional Jensen model and a double-beam lidar.

Example

In order to verify the effectiveness of the scheme of the present invention, the following simulation experiments are carried out on a wind turbine numbered A04 in a wind farm. There are two fans A03 and A05 near the fan A04. The azimuth angle of the fan A03 relative to the fan A04 is 35°, the connecting distance of the engine room is 316m, the azimuth angle of the fan A05 relative to the fan A04 is 218°, and the connecting distance of the engine room is 314m. The power utilization coefficients of the three fans are all 0.55, the lift coefficients are all 0.5, the radius of the wind rotor is 56.5m, the distance between the radar wind measurement point and the radar is 80m, and the angle between the laser emitted by the radar and the central axis of the fan is 30° , the wake attenuation coefficient is 0.075.

Taking the fan A04 as the downstream fan, the yaw error angle of the downstream fan A04 after compensation is shown in Figure 5. It can be seen that the corrected yaw error angle of the fan A04 has successfully eliminated the interference of the wake effect on the yaw error calculation. , so that the degree of distortion of the yaw error value in the wake region is significantly reduced. Based on the corrected yaw error angle of the downstream fan A04, the corresponding wind speed inflow angle is calculated when the plane of the rotor A04 of the fan is in the wake region. In the space of 360°, when the fan A03 is the upstream fan of the fan A04, in the wake area generated by the fan A03, the radius of the wake at the plane of the fan A04 is 68.8m, and the plane of the fan A04 is completely in the wake. The inflow wind direction angle of the area is 29°-44°, the inflow wind direction angle of the fan A04 in the wake area is 12°-28°, 45°-62°, and the rest of the inflow wind direction angle is the fan A04 wind wheel plane Completely in the natural wind speed zone. In 360° of space, when fan A05 is the upstream fan of fan A04, in the wake area generated by fan A05, the radius of the wake at the plane of fan A04 is 68.8m, and the plane of fan A04 is completely in the wake. The inflow wind direction angle of the area is 212°-225°, the inflow wind direction angle of the fan A04 in the wake area is 193°-211°, 226°-242°, and the rest of the inflow wind direction angle of the fan A04 wind wheel plane Completely in the natural wind speed zone.

According to the calculated inflow angle of the wind speed when the plane of the wind wheel of the fan A04 is in the wake region, the equivalent inflow wind speed of the fan A04 is calculated, and the power output value of the wake region of the fan A04 is finally calculated, as shown in Figure 6. Comparing the calculated power output value in the wake region with the actual power, the comprehensive error between the predicted power and the actual power is 4.26%. It can be seen that the correction method of the present invention is simple and effective, and can accurately calculate the power output value in the wake region of the fan.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage In the medium, when the computer program is executed, it may include the processes of the above-mentioned method embodiments. Wherein, any reference to memory, storage, database or other medium used in the various embodiments provided in this application may include non-volatile and/or volatile memory. Nonvolatile memory may include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain Road (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features It is considered to be the range described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (10)

1. The method for predicting the power of the fan in the wake zone based on the two-dimensional Jensen model and the double-beam laser radar is characterized by comprising the following specific steps of:

step 1, collecting inflow wind speed and inflow wind direction of an upstream fan, collecting yaw error angle of the upstream fan, collecting wind speed values measured by a left wind measurement point and a right wind measurement point of a double-beam laser radar of a downstream fan, and determining the distance and azimuth angle between the fans in a wind field;

step 2, calculating the wake flow radius of the cross section position of the radar wind measuring point of the downstream fan and the wake flow radius of the cross section position of the wind wheel plane of the downstream fan according to the two-dimensional Jensen model and the space and the azimuth angle between the fans;

step 3, judging whether two wind measuring points of the downstream fan radar are both in the natural wind speed area, one wind measuring point is in the wake area and the other wind measuring point is in the natural wind speed area, or the two wind measuring points are both in the wake area;

step 4, judging whether the downstream fan is positioned on the left side or the right side of the wake central axis according to the included angle between the connecting line of the upstream fan and the downstream fan and the wake central axis of the upstream fan;

step 5, calculating wind speed values measured by the compensated radar left and right wind measuring points of the downstream fan and a compensated yaw error angle of the downstream fan according to the position of the radar wind measuring point in the wind speed area;

step 6, judging whether the wind wheel plane of the downstream fan is completely in the natural wind speed area, partially in the wake area or completely in the wake area;

step 7, calculating the equivalent inflow wind speed of the downstream fan according to the position of the wind wheel plane of the downstream fan in the wake area;

and 8, calculating the power output value of the downstream fan.

2. The method for predicting the fan power in the wake zone based on the two-dimensional Jensen model and the double-beam laser radar as claimed in claim 1, wherein in the step 1, an SCADA system of the fan is used for collecting the inflow wind speed and the inflow wind direction of the upstream fan, a double-beam laser radar arranged above a cabin of the upstream fan is used for collecting a yaw error angle, a double-beam laser radar arranged above a cabin of the downstream fan is used for collecting wind speed values measured by a left wind measuring point and a right wind measuring point, and the distance and the azimuth angle between the fans in the wind field are determined according to the built site of the wind field.

3. The wake sector fan power prediction method based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 2, according to the distance and the azimuth angle between the two-dimensional Jensen model and the fan, the wake radius of the cross section position where the radar wind measurement point of the downstream fan is located and the wake radius of the cross section position where the wind wheel plane of the downstream fan is located are respectively calculated, and the specific method is as follows:

an included angle theta between the connecting line of the upstream fan and the downstream fan and the central axis of the wake of the upstream fan is defined_LComprises the following steps:

θ_L＝0.3C_T·β₁+θ_FWT-θ_x

in the formula, theta_xFor incident wind angle, θ_FWTAzimuth angle, β, of the upstream fan relative to the downstream fan₁Is the yaw error angle of the upstream fan, C_TIs the lift coefficient of the fan;

defining the vertical distance L between the cross section of a radar wind measuring point of the downstream fan and the upstream fan_lThe calculation formula is as follows:

L_l＝Ldcos(θ_L)-z₀ cos(α)

where Ld is the distance between the cabin links of the upstream and downstream fans, and z₀The distance between the wind point and the radar is measured for the radar of the downstream fan, and alpha is the downstreamThe included angle between the radar laser beam of the fan and the central axis of the downstream fan;

the wake radius calculation formula of the cross section position where the radar wind measurement point of the downstream fan is located is as follows:

R_l＝kL_l+r₀

where k is the wake attenuation coefficient, r₀Is the wind wheel radius of the fan.

The vertical distance between the section of the downstream fan wind wheel plane and the upstream fan is defined as L_wThe calculation formula is as follows:

L_w＝Ldcos(θ_L)

the calculation formula of the wake radius of the cross section position of the downstream fan wind wheel plane is as follows:

R_w＝kL_w+r₀

4. the method for predicting the fan power in the wake zone based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 3, it is determined whether two wind measuring points of the downstream fan radar are both in the natural wind speed zone, one wind measuring point is in the wake zone and the other wind measuring point is in the natural wind speed zone, or whether two wind measuring points are both in the wake zone, and the method specifically comprises the following steps:

if Ldsin (theta)_L)-z₀ sin(α)＞R_lIf the wind speed is higher than the set wind speed, the two wind measuring points of the downstream fan radar are both in a natural wind speed area;

if Ldsin (theta)_L)-z₀ sin(α)≤R_l&Ldsin(θ_L)+z₀ sin(α)＞R_lIf the wind speed is higher than the set wind speed, the radar of the downstream fan is positioned in the wake area at one wind measuring point, and the other wind measuring point is positioned in the natural wind speed area at the other wind measuring point;

if Ldsin (theta)_L)-z₀ sin(α)≤R_l&Ldsin(θ_L)+z₀ sin(α)≤R_lIf so, two wind measuring points of the downstream fan radar are both in the wake zone;

wherein Ld is the distance between the connecting lines of the engine rooms of the upstream fan and the downstream fan, and theta_LIs an included angle between the connecting line of the upstream fan and the downstream fan and the central axis of the wake flow of the upstream fan, z₀Is downstreamThe distance between the wind point and the radar is measured by the radar of the fan, alpha is the included angle between the radar laser beam of the downstream fan and the central axis of the downstream fan, R_lThe radius of the wake flow of the cross section where the radar wind measurement point of the downstream fan is located.

5. The method for predicting the power of the fan in the wake zone based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 4, whether the downstream fan is positioned on the left side or the right side of the central wake axis of the upstream fan is judged according to an included angle between a connecting line of the upstream fan and the downstream fan and the central wake axis of the upstream fan, and the specific method comprises the following steps:

if the included angle between the connecting line of the upstream fan and the downstream fan and the wake central axis of the upstream fan is smaller than 0, the downstream fan is positioned on the left side of the wake central axis, otherwise, the downstream fan is positioned on the right side of the wake central axis.

6. The method for predicting the power of the fan in the wake zone based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 5, the wind speed values measured by the compensated left and right wind measuring points of the downstream fan radar and the yaw error angle of the compensated downstream fan are calculated according to the position of the wind measuring point of the downstream fan radar in the wind speed zone, and the specific method is as follows:

(1) if the downstream fan is positioned on the left side of the central axis of the wake flow, the radar left wind measuring point is positioned in the natural wind speed area, and the right wind measuring point is positioned in the wake flow area, the wind speed compensation coefficient of the right wind measuring point is as follows:

in the formula, C_TIs the lift coefficient of the fan, k is the wake flow attenuation coefficient, r₀Is the radius of the wind wheel of the fan, L_lThe vertical distance between the cross section of the radar wind measurement point of the downstream fan and the upstream fan is obtained;

r_rkthe vertical distance between the position of the right wind measuring point and the central line of the wake flow plane is calculated by the following formula:

r_rk＝Ldsin(θ_L)-z₀sin(α)

where Ld is the distance between the engine room connecting lines of the upstream and downstream fans, and θ_LIs an included angle between the connecting line of the upstream fan and the downstream fan and the central axis of the wake flow of the upstream fan, z₀The distance between a radar wind point and a radar of a downstream fan is measured, and alpha is an included angle between a radar laser beam of the downstream fan and a central axis of the downstream fan;

the wind speed values measured by the compensated left and right wind measuring points of the downstream fan radar are as follows:

V_a＝V_los1

V_b＝V_los2/C_rw

in the formula, V_los1，V_los2Actual measured wind speed values of left and right wind measuring points of a radar of a downstream fan are respectively obtained;

(2) if the downstream fan is positioned on the right side of the central axis of the wake flow, the radar left wind measuring point is positioned in the wake flow area, and the radar right wind measuring point is positioned in the natural wind speed area, the wind speed compensation coefficient of the left wind measuring point is as follows:

in the formula, r_lkThe vertical distance between the position of the left wind measuring point and the central line of the wake flow plane is calculated by the following formula:

r_lk＝Ldsin(θ_L)-z₀ sin(α)

the wind speed values measured by the compensated left and right wind measuring points of the downstream fan radar are as follows:

V_a＝V_los1/C_lw

V_b＝V_los2

(3) if the downstream fan is positioned on the left side of the central axis of the wake flow and the radar left and right wind measuring points are positioned in the wake flow area, the wind speed compensation coefficients of the left and right wind measuring points are respectively as follows:

in the formula, r_lkAnd r_rkThe vertical distances between the positions of the left wind measuring point and the right wind measuring point and the central line of the wake flow plane are respectively calculated by the following formula:

r_lk＝Ldsin(θ_L)+z₀sin(α)

r_rk＝|Ldsin(θ_L)-z₀sin(α)|

the wind speed values measured by the compensated left and right wind measuring points of the downstream fan radar are as follows:

V_a＝V_los1/C_lw

V_b＝V_los2/C_rw

(4) if the downstream fan is positioned on the right side of the central axis of the wake flow and the radar left and right wind measuring points are positioned in the wake flow area, the wind speed compensation coefficients of the left and right wind measuring points are respectively as follows:

in the formula, r_lkAnd r_rkThe vertical distances between the positions of the left wind measuring point and the right wind measuring point and the central line of the wake flow plane are respectively calculated by the following formula:

r_lk＝|Ldsin(θ_L)-z₀sin(α)|

r_rk＝Ldsin(θ_L)+z₀sin(α)

the wind speed values measured by the compensated left and right wind measuring points of the downstream fan radar are as follows:

V_a＝V_los1/C_lw

V_b＝V_los2/C_rw

(5) if the left wind measuring point and the right wind measuring point of the downstream fan radar are both in the natural wind speed area, the wind speed values measured by the left wind measuring point and the right wind measuring point of the downstream fan radar after compensation are as follows:

V_a＝V_los1

V_b＝V_los2

according to the difference of the wind speed areas where the downstream fans are located, calculating the yaw error angle of the compensated downstream fan, wherein the specific formula is as follows:

7. the method for predicting the power of the fan in the wake zone based on the two-dimensional Jensen model and the double-beam laser radar according to claim 1, wherein in the step 6, whether the wind wheel plane of the downstream fan is completely in the natural wind speed zone, partially in the wake zone or completely in the wake zone is judged, and the specific method comprises the following steps:

if Ldsin (theta)_L)-r₁＞R_wThe plane of the wind wheel of the downstream fan is completely in the natural wind speed area;

if Ldsin (theta)_L)-r₁≤R_w&Ldsin(θ_L)+r₁＞R_wThe plane part of the wind wheel of the downstream fan is positioned in the wake area;

if Ldsin (theta)_L)-r₁≤R_w&Ldsin(θ_L)+r₁≤R_wThe plane of the wind wheel of the downstream fan is completely positioned in the wake area;

wherein r is₁The calculation formula is that the projection length of the radius of the wind wheel on the central line of the vertical wake flow is as follows:

r₁＝r₀ cos(0.3C_T·β₁+β₂)

wherein Ld is the distance between the connecting lines of the engine rooms of the upstream fan and the downstream fan, and theta_LIs an included angle between the connecting line of the upstream fan and the downstream fan and the central axis of the wake flow of the upstream fan, R_wIs the tail of the cross section position of the downstream fan wind wheel planeRadius of flow, r₀Is the radius of wind wheel of the fan, beta₁Is an upstream fan yaw error angle, beta₂For compensated yaw error angle of downstream fan, C_TIs the lift coefficient of the fan.

8. The wake sector fan power prediction method based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 7, the equivalent inflow wind speed of the downstream fan is calculated according to the difference that the wind wheel plane of the downstream fan is positioned in the wake sector, and the specific method is as follows:

(1) if the plane of the wind wheel of the downstream fan is completely in the natural wind speed area, the equivalent inflow wind speed of the downstream fan is as follows:

wherein u is₀The inflow wind speed of the upstream fan.

(2) If the plane part of the downstream fan wind wheel is positioned in the wake area, the area of the downstream fan wind wheel plane in the wake area is as follows:

wherein R is_wIs the wake radius of the cross section position of the downstream fan wind wheel plane, r₁Is the projection length of the radius of the wind wheel on the central line of the vertical wake;

let O be₁，O₂Is the wake flow center and the downstream fan wheel center of the downstream fan wheel plane, B is any intersection point of the wake flow area edge and the downstream fan wheel edge of the downstream fan wheel plane, and theta₁Is a connecting line O₁O₂And a connection line O₁Angle of B, θ₂Is a connecting line O₁O₂And a connection line O₂The calculation formula of the included angle B is as follows:

wherein L is_RIs the vertical distance of the downstream fan center from the upstream fan wake centerline:

L_R＝Ldsin(θ_L)

wherein Ld is the distance between the connecting lines of the engine rooms of the upstream fan and the downstream fan, and theta_LThe included angle between the connecting line of the upstream fan and the downstream fan and the central axis of the wake flow of the upstream fan is formed;

the wind wheel area of the downstream fan is as follows:

S＝πr₀ ²

wherein r is₀Is the radius of the wind wheel of the fan.

The projected area of the wind wheel on the central line of the vertical wake flow is as follows:

S₁＝πr₁ ²

wherein r is₁The length of the projection of the radius of the wind wheel on the central line of the vertical wake flow;

wind speed u in wake zone_rThe calculation formula is as follows:

in the formula, C_TIs the lift coefficient of the fan, k is the wake flow attenuation coefficient, r₀Is the radius of the wind wheel of the fan, L_wThe vertical distance between the cross section of the downstream fan wind wheel plane and the upstream fan, r is the vertical distance between any point of the downstream fan wind wheel plane and the center line of the tail flow plane, u is the vertical distance between any point of the downstream fan wind wheel plane and the center line of the tail flow plane₀The inflow wind speed of an upstream fan;

the equivalent inflow wind speed calculation formula of the downstream fan is as follows:

wherein, a and b are integral upper and lower limits, and the values are as follows:

a＝L_R-r₁

b＝R_w

(3) if the plane part of the wind wheel of the downstream fan is positioned in the wake area, the equivalent inflow wind speed calculation formula of the downstream fan is as follows:

wherein,

a＝L_R-r₁

b＝L_R+r₁

9. the method for predicting the power of the fan in the wake zone based on the two-dimensional Jensen model and the dual-beam laser radar as claimed in claim 1, wherein in the step 8, the power output value of the downstream fan is calculated by a specific formula:

wherein rho is air density, S is downstream fan wind wheel area, C_pFor the downstream fan power utilization factor,

is the equivalent inflow wind speed of a downstream fan, beta₂The yaw error angle of the downstream fan after compensation.

10. Two-dimensional Jensen model and double-beam laser radar-based wake flow area fan power prediction system is characterized by comprising:

the data acquisition module is used for acquiring the inflow wind speed and the inflow wind direction of the upstream fan, acquiring the yaw error angle of the upstream fan, acquiring the wind speed values measured by the left and right wind measuring points of the dual-beam laser radar of the downstream fan, and determining the distance and the azimuth angle between the fans in a wind field;

the wake flow radius calculation module is used for calculating the wake flow radius of the cross section position of the radar wind measuring point of the downstream fan and the wake flow radius of the cross section position of the wind wheel plane of the downstream fan according to the two-dimensional Jensen model and the space and the azimuth angle between the fans;

the wind measuring point position judging module is used for judging whether two wind measuring points of the downstream fan radar are both in a natural wind speed area, one wind measuring point is in a wake area, the other wind measuring point is in the natural wind speed area, or the two wind measuring points are both in the wake area;

the fan position judging module is used for judging whether the downstream fan is positioned on the left side or the right side of the wake central axis according to an included angle between the connecting line of the upstream fan and the downstream fan and the wake central axis of the upstream fan;

the compensation module is used for calculating wind speed values measured by the compensated radar left and right wind measuring points of the downstream fan and a yaw error angle of the compensated downstream fan according to the position of the radar wind measuring point in the wind speed area;

the wind wheel plane position judging module is used for judging whether the wind wheel plane of the downstream fan is completely positioned in a natural wind speed area, a partial wake area or a wake area;

the equivalent inflow wind speed calculation module is used for calculating the equivalent inflow wind speed of the downstream fan according to the position of the wind wheel plane of the downstream fan in the wake flow area;

and the power output calculation module is used for calculating the power output value of the downstream fan.

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