Research On Wind Turbine Fault Simulation Based On Current Signal Analysis

With the rapid development in recent years, Wind power is playing a more and more important role. But as the growth of wind turbines capacity and increasing complication of operation condition, failures of wind turbine occur frequently and the maintenance cost increases greatly. So the importance of the wind turbine fault diagnosis is obvious. This paper chose generator and gearbox as the research object and simulations were carried out to find the fault feature, specific as follows:The one-stage planetary gear and two-stage spur gear fixed axis system of wind turbine are chosen as the research object, coordinate transformation is used to deal with the motion analysis contradiction between planetary gear train and fixed gear train. Lumped parameter method is used so the differential motion equations of gearbox reverse- lateral vibration are established. Calculation of an example is given to find out how meshing stiffness vary with gear fault. Then the gear fault was simulated by changing the meshing stiffness of the fault gear. The simulation of the gearbox model combined with wind turbine generator system(WTGS) model was carried out. The output current was analyzed to find the fault feature.The generator model was established on simulink platform using the generator voltage equations, flux linkage equations, the equation of motion and torque equation. The asymmetric matrix was introduced to describe the parameters change of stator failure, then the new three-phase asynchronous motor model was established. The simulation was carried out and the fault severity was simulated by changing the asymmetric matrix, and the current of four conditions were collected.Time domain analysis was conducted to find out the influence of stator interturn short circuit fault to current amplitude. Then the spectrum analysis was conducted to get the stator interturn short circuit fault characteristics. Then a simplified model of the asynchronous generator was established and rotor broken bar fault was simulated by changing external resistance of the rotor. The time domain analysis was carried out on the rotor speed and three phase current of stator to find their change when there was rator fault. At last, zoom spectrum analysis was carried out to find the failure frequency of stator current.This paper proposed simplified model for gearbox and generator fault diagnosis, thus solving the complication of fault model establishing. Besides, fault diagnosis based on current signal analysis is a valuable method.