Research On Stator Current Detection System And Fault Analysis Of Double-fed Wind Turbine

In recent years,the wind power industry has developed rapidly in the world.The proportion of wind turbines in the new energy power equipment is getting higher and higher,and they are gradually spread all over China.Double-fed wind turbine is the mainstream wind turbine at present.However,due to its harsh environment,the failure of the turbine often occurs.Therefore,the detection and fault analysis of the working state of the fan have become the focus of the industry.In this dissertation,based on the method of stator current detection,the current at the stator end of the fan tower is processed and analyzed,and the frequency component of the current signal is found,and finally the fault diagnosis is carried out.The main research contents of this dissertation are as follows:1.In view of the problem that the weak fault characteristics of double-fed wind turbines are easy to be submerged by 50 Hz fundamental interference signals,starting from the direction of hardware circuit,this dissertation introduces the method of attenuation of fundamental interference signals based on double T-notch filter,which mainly includes: Current sensor selection,first-order high-pass and low-pass filter,double-T 50 Hz notch filter,LM393 shaping circuit,programmable six-order Butterworth high-pass and low-pass filter based on 4053,12th-order Butterworth low-pass filter based on relay and dip switch amplifier circuit,etc.2.Using the data acquisition card and VB6.0 advanced language to write the upper computer stator current detection system software,to realize the analysis of signals,mainly including: data acquisition module,data analysis module(functional interface introduction,time domain analysis,frequency domain analysis),fault diagnosis module(fault characteristic frequency calculation,fault diagnosis report),data acquisition card and the upper computer software experiment;3.The clamp type high-precision current transformer,Roche coil current sensor and hardware circuit were tested with data acquisition card and upper computer software respectively,and the stator current detection system instrument was developed: "WGM-1700 wind turbine current detection analyzer" tester;4.The fault simulation experiment of stator current detection system is carried out.Under the precondition that the fault frequency component can be displayed in the spectrum,the identification ability of the system to the fault frequency component is determined.The current signals at the lower stator end of the double-fed wind turbine tower are collected and analyzed.It is confirmed that the system can effectively attenuate the fundamental frequency interference signal,so that the weak fault characteristic frequency components can be displayed,which provides a solid foundation for the subsequent improvement of the whole system and the unit fault diagnosis.