Vibration Fault Diagnosis Technology And Load Reducing Method For MW Variable Speed And Variable Pitch Wind Turbine

MW variable speed and variable pitch wind turbine(VSVPWT)is very important part in power system,and is main wind energy application forms.As of 2017,the proportion of wind power to total power generation is 4%,and the most effective way to wind power is MW variable speed and variable pitch wind turbine.Because of the complexity and distribution of wind turbine,the traditional operation and maintenance mode driven by faults used in hydraulic electrogenerating and thermal power can not effectively support the development of wind power industry,and active operation and maintenance mode based on conditions of wind turbine will become mainstream mode,and it is the only way which must be done for unattended operation in wind farm.VSVPWT is composed of rotating mechanical components and structural components,and its vibration is complex superposition of these two type components vibration,which results in paroxysmal and sporadic characteristics of vibration faults.The technology used in traditional rotating machinery is not effective to VSVPWT faults diagnosis,particularly to multiple components coupling faults.In this paper,the topic is to develop the system level faults diagnosis technology and load reducing method used in VSVPWT,and research process and production are as follows:1.Arming to solving the problem of air wheel unbalance during modeling and simulation cased by wind shear and tower shadow effect in classical blade element momentum,the modeling method of air wheel brake disc is proposed when blades of wind turbine is unbalanced and pitch angles are different,and the key variate mathematical expression during load calculating process which are named axial and circumferential factors is derived.Both simulation results and field data prove that this method is valid.In addition,the simulation and field data analyzing results show that 3P vibration caused by tower shadow is the most loading fluctuating characteristics,and wind shear has little effect to loading variety.2.The blade loading fluctuating rate at different work point is different,which is caused by blade aerodynamic characteristics.At some work point,the loading fluctuating rate is huge when wind change,which leads to sudden,accidental and intermittent faults.The faults diagnosis method based vibration characteristic waveform is proposed in this paper,and proved effectively in sudden and accidental faults diagnosis.3.The consistency between wind turbine yaw system and sudden diagnosis is developed and proved effectively by field data in this paper.The consistency is applied to diagnose yaw system faults by analyzing tower sudden faults.4.Arming to resolve the problem that acceleration sensor can not support the faults diagnosis because of vibration transmission disturbance,the blade faults diagnosis method based on blade strain placed on blade root part is proposed in this paper,and filed data analyzing results proved this method effective.Moreover,blade vibrating monitoring by directly contacting sensors is limited in sensors installation and data transmission,and alternative method is proposed in this paper,which is that wind turbine nacelle swing sensors are used to diagnose baled faults,which can improve monitoring efficiency and reducing monitoring cost.5.The load reducing method based on TMD(Tuned Mass Device)is proposed and applied in VSVPWT.The reducing load effectiveness of TMD is analyzed under some operation conditions of wind turbine,and the analysis results shows that the reducing load effectiveness under rated power can reach above 40%,which means TMD can improve the safety and reliability of wind turbine,and TMD is with good practical value.