A damage diagnosis method for wind turbine blades based on natural frequency

Abstract

The invention discloses a wind turbine blade damage diagnosis method based on natural frequency. The wind turbine blade damage diagnosis method based on the natural frequency comprises the following steps: establishing a single damage position parameter of a wind turbine blade based on a principle that the ratio of any two orders of natural frequency change or the square ratio of the change of thedamaged wind turbine blade is only related to a damage position; based on the single damage position parameter of the wind turbine blade, establishing parameter databases of different damage positions, and providing a blade damage positioning parameter to form blade damage interval positioning; based on a mapping relation between the blade damage positioning parameter and the relative position ofsections, implementing accurate positioning in a blade damage section; and based on the principle that the ratio of the first-order natural frequency change of the damaged blade to the first-order natural frequency is only related to the damage degree of the blade, obtaining a damage degree relation formula of the damage position, and implementing accurate identification of the damage degree. According to the invention, the damage position can be located accurately and the damage degree can be recognized only by measuring the natural frequency of an online blade through a sensor, and the positioning method is simple and efficient.

Description

technical field [0001] The invention relates to the field of fan fault diagnosis, in particular to a method for diagnosing damage to wind turbine blades based on natural frequencies. Background technique [0002] Wind turbine blades are an important part of wind turbines and a device for capturing wind energy. Their cost accounts for about 25% of the installed cost. The performance directly affects the normal operating efficiency and service life of wind turbines. Due to the harsh working environment and complex and changeable working conditions of the blades, the blades will be damaged to varying degrees during operation. Damage will affect the performance of the entire wind turbine and lead to major safety accidents, so it is of great significance to accurately locate and diagnose blade damage. [0003] Although many methods have been developed in the research of damage identification based on structural vibration and system dynamic parameters, due to the long span of win...

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Problems solved by technology

[0003] Although many methods have been developed in the research of damage identification based on structural vibration and system dynamic parameters, due to the long span of wind turbine blades and the relatively complex terrain, these methods have certain limitations in practical applications (such as inability to accurately identify location and damage degree of the damage), so it is urgent to propose a new method of damage identification based on natural frequency with simple and high positioning accuracy

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