Method for monitoring pneumatic unbalance of fan blades

Abstract

The invention discloses a method for monitoring pneumatic unbalance of fan blades. The method comprises the following steps that firstly, two mounting points in a root area of each blade of a fan are selected, a load sensor is mounted on each mounting point, loads of the six mounting points of three blades at different wind speeds v through the load sensors, the real-time azimuth angle theta of the three blades, the gravity of the three blades is measured, the measured data are substituted into a formula to obtain the aerodynamic force Fx of the three blades at different wind speeds v, a v-Fx curve is fitted according to the aerodynamic force Fx of each blade at different wind speeds v, finally the obtained three curves are drawn in a graph, comparing is carried out on the three curves, if the three curves are approximate or coincide, the three blades are in a pneumatic balance state, and otherwise, the blades are in a pneumatic unbalance state. Through the method, whether the blades are in the pneumatic unbalance state or not can be found in time, and the problem that the service life and the operation safety of a unit are influenced by the increase of the load of the whole machine due to pneumatic imbalance of the blades is avoided.

Description

technical field [0001] The invention relates to the technical field of aerodynamic unbalance monitoring of fan blades, in particular to a method for monitoring aerodynamic unbalance of fan blades. Background technique [0002] With the continuous development of wind power technology, the output power of wind turbines has become larger, the towers are higher, the blades are longer, and the operating environment of wind turbines is more complex, so the wind rotor imbalance caused by blade mass imbalance and aerodynamic imbalance Faults have become a serious problem that threatens the safe operation of wind turbines and affects the performance of wind turbines. [0003] At present, the mass imbalance can be quickly diagnosed by conventional diagnostic methods and the blade weight can be re-balanced. However, it is not easy to find the aerodynamic unbalance fault in the early stage, and it is difficult to judge whether it is aerodynamic unbalance by conventional diagnostic meth...

AI Technical Summary

Problems solved by technology

[0005] 1) Blade manufacturing error: 0-degree positioning error in blade manufacturing; 2) Blade installation error: there will be a certain measurement error in the calibration of the blade installation angle; 3) Execution error of the pitch mechanism: the angle of each blade cannot be adjusted during the pitch change process. Maintain complete synchronization, resulting in execution errors; 4) Blade damage status: a blade is damaged, resulting in different forces on each blade, resulting in aerodynamic imbalance

[0006] The impact of the aerodynamic imbalance of the blades: 1) The periodic load of the fan increases; 2) The vibration of the fan increases; 3) Damage to the components inside the fan, such as main shaft, yaw, pitch damage, etc.; 4) Fan reduction in power generation

[0007] The commonly used blade aerodynamic unbalance detection method is to judge whether there is an imbalance by analyzing the vibration signal of the nacelle, or use the imaging of the blade on the ground to judge whether the wind force is balanced, but these methods need to analyze and compare the historical data of the unit, and the amount of data is large , the calculation is complex, and requires a certain experience in vibration analysis and image processing technology. The characteristic quantities analyzed are indirect results, and it is difficult to directly reflect the aerodynamic imbalance of the blade.

Moreover, due to random changes in wind conditions, it is difficult to select reliable similar working conditions for comparative analysis

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