Study On Fault Diagnosis Of Wind Power Transmission System

In the 21 st century,due to the relative lack of resources,environmental pollution is becoming more and more serious,and wind energy has been regenerated due to cleanliness and has attracted people’s attention.Wind power generation has been developed and utilized on a large scale due to its relatively mature technology,safety and energy saving.Since the wind power equipment is usually located in a remote area,the maintenance is not easy,and the intermittent and unstable wind energy causes the wind power generator to be subjected to different degrees of impact load,and the drive system of the wind turbine is highly prone to failure.Aiming at the partial deformation and dynamic law of gearbox and transmission shaft of key components of wind power transmission system,the fault diagnosis method of wind power transmission system is discussed.The vibration gearbox test and diagnosis is discussed,the wind turbine gearbox bearing load is calculated,the force analysis of the gearbox drive shaft is discussed,find the appropriate additional force angle,and get the range of bearing load,give the stress distribution of the gearbox box.The method of diagnosis based on gearbox strain test is established;and the torsional vibration diagnosis of wind power transmission system is studied,and the torsional vibration test and signal processing are studied,that is,the magnetoelectric sensor is used,and the fault signal containing the dead point in the torsional vibration measurement is proposed.A two-line approximation algorithm that continuously approaches zero voltage,effectively removes the dead pixels in the fault signal,so that the health signal can be transformed,the harmonic extraction algorithm of the instantaneous speed is given,and the variation law of the harmonic functions of the various speeds is discussed.Establish a diagnostic method for torsional vibration measurement.Aiming at the torsional vibration problem of wind power transmission system,the mechanical properties of the leaf spring torsional vibration damper which can be used to reduce vibration are discussed.Based on the Bernoulli-Euler beam model,the torsional stiffness and strength calculation method of the damper is given.The element method was used to test the stiffness of the leaf spring,and the influence of the size of the copper gasket and the thickness of the reed on the stiffness and strength of the reed was further studied.Aiming at the vibration test of long-flexible structures such as long drive shafts,blades and columns in wind power transmission system,the influence of the vibration characteristics on the quality of the sensor is studied,and the correction method based on perturbation method is established.The feasibility of the method was verified on the bench.The details and results of this article are as follows:1)It is pointed out that wind power has been promoted and used as a new energy source in China.The calculation of gear transmission force and bearing reaction force of high-speed,middle and low-speed shaft of wind power gearbox is given.The stress value of gearbox is calculated by finite element method,and established a diagnostic method for stress;2)The torsional vibration measurement calculation of the wind power transmission system is given.The voltage signal similar to the cosine wave is collected by the method of installing the gear plate and the sensor.Due to the high sampling frequency and the tooth shape error,the test result is often distorted.The bad points of up and down fluctuations appear near the zero voltage of the rising edge of the voltage signal.These faulty dead points bring inconvenience to the torsional vibration measurement signal processing of the transmission shaft.A two-line approximation algorithm is proposed,which can effectively remove the abnormal points and perform torsional vibration measurement of the drive shaft;3)The harmonic characteristics of the rotational speed of the shaft are discussed.After the fourier series expansion,the amplitude and phase angle of the harmonic functions of the instantaneous rotational speed are extracted,and the variation of the amplitude and phase angle is studied.The results show that the torsional response quickly stabilizes,the diagnostic response of the test response is normal;4)In order to reduce the torsional vibration of the wind power transmission system,a leaf spring torsional vibration damper is installed at the output shaft end to adjust the natural frequency of the shaft system and reduce the shaft torque peak.The stiffness and stress calculation model of the leaf spring is deduced,and the Fortran95 program is used to solve the stress value,which provides a reference for the development and use of the torsional vibration damper.In the study of the stress and deformation of the damper,the equipment of the damper was diagnosed to be operating normally;5)In the long-axis structural vibration test of wind power transmission system,the sensor mass has a great influence on the acceleration measurement.In order to study the natural frequency variation law of the slender structure,the dynamic model considering the sensor quality is derived,and the matrix perturbation is given.The correction method shows that the results of the matrix perturbation method are close to the theoretical solution when the structure parameters change slightly,which provides a calculation tool for the long-axis structure test of the wind power transmission system.