Research On The Modeling And Simulation Of Wind Turbine Rotor Imbalance Fault

The wind turbine rotor, which is the important component of the wind turbine, has abig effect on the security and stability operation of wind turbine, the rotor imbalance fault isthe main fault of the wind turbine rotor, in particular, the wind turbine with increasingcapacity and rotor diameter, the height of the tower is increasing too, the fault can causehuge vibration of the overall structure, and also the fatigue stress in the components whichaffect the lifetime of the wind turbines.Rotor imbalance fault includes the rotor mass imbalance fault and aerodynamicasymmetric fault. This paper outlines the mechanism of these two faults and illustrated indetail how the two faults cause the vibration of the nacelle and fluctuation of the electricpower, pointed that the fluctuation of the electric power under the mass imbalance fault iscaused by the gravity of the imbalance mass which effect the rotor output torque, whileunder the aerodynamic asymmetric fault, the aerodynamic force fluctuates, then the rotoroutput torque and electric power fluctuates, that is the.aerodynamic model is coupled withthe tower vibration model.In this paper, based on platform of matlab/simulink, the wind turbine model (includingthe constant speed wind turbine and variable speed double-fed induction generator windturbine) under the normal state and rotor imbalance state is established, the aerodynamicforce is calculated by the Blade Element Momentum(BEM) theory, the tower vibration iscalculated by the assumed mode method, the vector is used in the double-fed inductiongenerator to achieve the decoupling of active and reactive power, the tower vibration signaland electric signal is simulated, the simulation results shows that for the constant speedwind turbine, the mass imbalance fault and aerodynamic fault can cause the1st frequencyin the tower side-to-side vibration signal and for-aft vibration signal respectively, and bothcan cause the1st frequency of the wind turbine rotor in the electric powe r, while for thedouble-fed induction wind turbine generator, the tower vibration signal is similar with thatin constant speed wind turbine, and it’s worth noting that with the rotor speed changes, theresonance occurs when the rotor speed close to the1st natural frequency of the tower, andfor the electric power signal, compared with the constant speed wind turbine, the1st frequency it contained is not significant, but the fault characteristic may be revealed inother electric signals.