CN116044676A - Fan clearance detection method - Google Patents

Abstract

The invention discloses a method for detecting the headroom of a wind turbine. The steps include: (1) pointing at least one photographing device at the side of the impeller of the wind power generator; plane, take the images of the blade tip and the tower when each blade of the impeller turns to the lowermost end; (3) measure the pixel distance from the blade tip of the blade in each captured image to the tower, and calculate the Clearance distance; also includes after step (3), according to the measurement results, comparing whether the clearance distances of each blade are equal, thereby determining whether the impeller is balanced or detecting whether the clearance distance of each blade is in a dangerous state. The detection process of the fan headroom detection method of the invention is simple, the data is easy to calculate, and the detection equipment is simple to install and low in cost.

Description

Fan headroom detection method

technical field

The invention relates to the technical field of fan headroom detection, in particular to a fan headroom detection method.

Background technique

With the continuous improvement of the single power of wind turbines, the wind rotor blades are also constantly developing in the direction of large-scale. But the longer the blade, the more risk of blade sweeping. Once the blade sweeps the tower, it may cause damage to the blade, and even worse, it will cause serious accidents such as the unit falling down.

In recent years, the detection of blade clearance through video or laser technology has become a mainstream technology. Blade clearance refers to the minimum distance between the blade and the tower during the operation of the blade. However, this mainstream technology requires cameras or laser transmitters to be installed on the cabin or tower of the unit for measurement. The installation process is complicated, the clearance algorithm is complicated, and the cost is high.

Therefore, there is an urgent need for a fan headroom detection method with simple detection process, easy calculation of data, simple installation of detection equipment and low cost.

Contents of the invention

The object of the present invention is to provide a method for detecting the headroom of a blower fan, the detection process is simple, the data is easy to calculate, and the detection equipment is easy to install and low in cost.

In order to achieve the above object, the technical solution of the present invention is: a fan headroom detection method, which includes the following steps:

(1) Point at least one photographing device to the side of the wind turbine's impeller;

(2) Rotate the impeller, along with the plane of rotation formed by the rotation of the impeller, take images of the blade tip and the tower when each blade of the impeller turns to the lowermost end;

(3) Measure the pixel distance from the tip of the blade to the tower in each captured image, and calculate the headroom distance of each blade.

Preferably, after step (3), comparing whether the clearance distances of the blades are equal according to the measurement results, so as to determine whether the impeller is balanced or detect whether the clearance distances of the blades are in a dangerous state.

Preferably, the position of the camera in the step (1) is set such that the shooting direction is perpendicular to the axis of rotation of the impeller.

Preferably, the rotation plane in the step (2) is a plane formed by the rotation of the impeller composed of three blades and the hub around the center line of the hub.

Preferably, the clearance distance calculated in the step (3) is C=c×L/l, wherein c is the measured pixel distance from the blade tip to the tower, and L is the distance between the blade tip and the blade tip. The cross-sectional diameter of the tower at the same horizontal plane, l is the pixel distance of the corresponding section of the tower.

Preferably, in the captured image, when the blade is at the lowest end is the moment when the shooting line of the shooting device is tangent to the motion trajectory of the blade, so it is necessary to correct the calculated clearance distance. The position where the blade is at the moment of minimum headroom, the corrected distance is: Δr1=R×(1-cosα), R is the radius of the impeller, and α is the angle between the shooting direction of the camera and the horizontal plane.

Preferably, when the running track of the blade is shown as an ellipse in the image, it indicates that the impeller has yaw, and the yaw angle of the impeller is β=arcsin(b/R), wherein the radius of the impeller is R, and the minor axis length of the elliptical trajectory is 2b.

Preferably, the true clearance distance C=C0/COSβ+L/2(1/COSβ-1) when the impeller yaws, wherein, L/2 is the tower at the same level as the blade tip The radius of the cross section, C0 is the clearance distance calculated in step (3).

Preferably, the distance between the shooting device and the tower is ≤1000m.

Preferably, the distance between the shooting device and the tower is 100m-300m.

Preferably, the photographing device adopts a camera or a laser device.

After adopting the above scheme, the air blower headroom detection method of the present invention has the following beneficial effects:

1, the present invention is by setting the shooting equipment such as camera or laser device under the tower frame or bottom surface, photographs the tip of each blade from the side of the impeller to the headroom distance of the tower frame, can judge whether to be in a dangerous state by the headroom distance of each blade, It is also possible to judge whether the impeller is balanced by comparing whether the clearance distances of the three blades are equal. The detection process is simple, the data is easy to calculate, and the detection equipment is simple to install and low in cost;

2. By correcting the position of the blade at the moment of the minimum clearance when the calculated clearance distance is calculated, the real clearance distance can be obtained more accurately, so as to better judge whether it is in a dangerous state and whether the impeller is balanced;

3. Whether the impeller is yaw can be determined through the captured blade running track, and the real headroom distance detection under the yaw state of the unit can be realized by using a simple algorithm through the measured yaw angle.

Description of drawings

Fig. 1 is the front view schematic diagram of the shooting direction of the shooting device for calculating the blade clearance distance in the present invention;

Fig. 2 is a schematic left view of the shooting direction of the shooting device for calculating the blade clearance distance in the present invention;

Fig. 3 is the front view schematic diagram of the shooting direction of the shooting equipment of the actual blade clearance distance of the present invention;

Fig. 4 is a schematic left view of the shooting direction of the shooting device of the actual blade clearance distance of the present invention;

Fig. 5 is a schematic diagram of the yaw angle algorithm when yaw occurs as shown in Fig. 4;

Fig. 6 is a schematic diagram of the correction algorithm of the present invention when the impeller is yaw.

Below in conjunction with accompanying drawing, the present invention will be further described by embodiment;

Detailed ways

The present invention will be described below according to the embodiments shown in the accompanying drawings. It can be thought that embodiment disclosed this time is an illustration in every point, and is not restrictive. The scope of the present invention is not limited by the description of the following embodiments but only by the scope of the claims, and includes the same meaning as the scope of the claims and all modifications within the scope of the claims.

With reference to Fig. 1 and shown in Fig. 2, fan headroom detection method of the present invention comprises the following steps:

(1) Shooting at least one shooting device against the side of the impeller of the wind turbine, the shooting device may be a camera or a laser device. As shown in Figure 2, the present embodiment adopts the camera 1, and the camera 1 is placed against the side of the impeller 2, and the shooting direction of the camera 1 of the present embodiment is the direction when a blade 3 of the impeller 2 is at the lowest end. 2 is composed of three blades 3 connected to the hub 4, and integrally installed on the upper end of the tower 5, the three blades 3 are installed in the axial direction of the hub 4, and the three blades 3 are evenly distributed along the circumferential direction, and the camera 1 is set For the shooting direction to be perpendicular to the axis of rotation of the impeller 2, the distance between the camera 1 and the tower 5 is ≤1000m, preferably 100m-300m;

(2) Turn the impeller 2, and the three blades 3 rotate with the center line of the hub 4 to form a rotation plane A, and the images of the blade tip 6 and the tower 5 when each blade 3 of the impeller 2 turns to the lowermost end are taken by the camera 1, namely Shoot the blade tip 6 and the tower 5 along the shooting line 7;

(3) Measure the pixel distance from the tower 5 to the tower 5 when the tip 6 of the blade in each captured image is located at the lowest end, and calculate the headroom distance of each blade 3 . The formula for calculating the clearance distance is: C=c×L/l, where C is the clearance distance, c is the measured pixel distance from the blade tip 6 to the tower 5, and L is the distance between the tower 5 and the blade tip 6 on the same horizontal plane. Cross-sectional diameter, l is the pixel distance of the corresponding section of the tower 5.

By comparing the clearance distance C of each blade 3 in step (3), it can be determined whether the impeller 2 is balanced or whether the clearance distance C of each blade 3 is in a dangerous state. When the clearance distance C of the three blades 3 is equal, it means that the impeller 2 is balanced , otherwise it is unbalanced.

As shown in FIG. 3 , in the photographed image, when the blade 3 is at the lowest end, it is the moment when the shooting line of the camera 1 is tangent to the motion track of the blade 3 , not when the blade 3 is at the minimum clearance during rotation. Therefore, it is necessary to correct the position where the blade is at the minimum clearance when calculating the clearance distance. The modified clearance distance is:

Δr1=R×(1-cosα), where R is the radius of the impeller 2, and α is the angle between the shooting direction of the camera 1 and the horizontal plane.

Referring to Figure 4, when the running track of the blade 3 is displayed as an ellipse B in the image, it indicates that the impeller 2 has yaw, and referring to Figure 5, the angle β of the yaw of the impeller 2=arcsin(b/R ), where R is the radius of the impeller 2 and b is the length of the semi-minor axis of the elliptical trajectory. Referring to Fig. 6, when the impeller 2 yaws, the actual clearance distance of each blade 3 is C=C0/COSβ+L/2(1/COSβ-1), where C0 is the clearance calculated by step (3) The distance, L/2, is the cross-sectional radius of the tower 5 at the same level as the blade tip 6 . The formula results from the following calculation steps:

C=C1+C2(1)

C1=C0/COSβ(2)

C2=L/2COSβ-L/2(3)

From (1), (2) and (3), it can be obtained that C=C0/COSβ+L/2(1/COSβ-1).

The present invention can also be provided with photographing equipment such as laser equipment by setting camera 1 under tower frame 5 or bottom surface, and the blade tip 6 of each blade 3 is taken from the left side of impeller 2 to the headroom distance of tower frame 5, by each blade 3 The clearance distance of the three blades 3 can be used to determine whether it is in a dangerous state. It can also be judged whether the impeller 2 is balanced by comparing the clearance distances of the three blades 3. The detection process is simple, the data is easy to calculate, and the detection equipment is easy to install and low in cost; When the calculated clearance distance is at the position of the blade at the moment of minimum clearance, the real clearance distance can be obtained more accurately, so as to better judge whether it is in a dangerous state and whether the impeller is balanced; the impeller can be determined by taking the running track of the blade 3 Whether to yaw or not, a simple algorithm is used to detect the true clearance distance of the crew under the yaw state through the measured yaw angle.

The above-mentioned embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (11)

1. A fan headroom detection method is characterized in that: comprise the steps: (1) Point at least one photographing device to the side of the wind turbine's impeller; (2) Rotate the impeller, along with the plane of rotation formed by the rotation of the impeller, take images of the blade tip and the tower when each blade of the impeller turns to the lowermost end; (3) Measure the pixel distance from the tip of the blade to the tower in each captured image, and calculate the headroom distance of each blade. 2. The fan headroom detection method according to claim 1, further comprising, after the step (3), comparing whether the headroom distances of the blades are equal according to the measurement results, thereby determining whether the impellers are balanced or detecting whether the blades are balanced or not. Whether the clearance distance of the blade is at risk. 3 . The method for detecting the headroom of a fan according to claim 1 , wherein the position of the camera in the step (1) is set such that the shooting direction is perpendicular to the axis of rotation of the impeller. 4 . 4. The air blower headroom detection method according to claim 1, wherein the plane of rotation in the step (2) is that the impeller composed of three blades and the hub rotates around the centerline of the hub formed plane. 5. The fan headroom detection method according to claim 1, characterized in that, the headroom distance C=c×L/l calculated in the step (3), wherein c is the measured blade tip to the The pixel distance of the tower, L is the cross-sectional diameter of the tower at the same level as the blade tip, and l is the pixel distance of the corresponding section of the tower. 6. The fan headroom detection method according to claim 5, characterized in that, in the captured image, when the blade is at the lowest end, the shooting line of the shooting device is tangent to the motion track of the blade. time, so it is necessary to correct the calculated clearance distance when the blade is at the minimum clearance moment position, the correction distance is: △r1=R×(1-cosα), R is the radius of the impeller, and α is the position taken by the camera The angle between the direction and the horizontal plane. 7. The fan headroom detection method according to claim 5, wherein when the running track of the blade is shown as an ellipse in the image, it indicates that the impeller has yaw, and the angle of the yaw of the impeller is β=arcsin(b/R), wherein the radius of the impeller is R and the minor axis length of the elliptical trajectory is 2b. 8. The air blower headroom detection method according to claim 7, characterized in that, the real headroom distance C=C0/COSβ+L/2(1/COSβ-1) when the impeller yaws, wherein, L/ 2 is the cross-sectional radius of the tower at the same level as the blade tip, and C0 is the clearance distance calculated in step (3). 9. The method for detecting the headroom of a fan according to claim 1, wherein the distance between the shooting device and the tower is ≤1000m. 10. The method for detecting clearance of a fan according to claim 9, wherein the distance between the photographing device and the tower is 100m-300m. 11. The method for detecting the headroom of a fan according to claim 1, wherein the photographing device is a camera or a laser device.

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