Fault Diagnosis for Blade Mass Imbalance of Wind Turbines in View of Wind Speed Spatiotemporal Distribution

Abstract

Considering the spatiotemporal distribution of natural wind speed and the influence of wind shear (WS) and tower shadow effect (TSE), the influence of blade mass imbalance fault on the electrical characteristics of DFIG WT is analyzed. Firstly, the theoretical analysis are carried out, and the analytical expressions and their variation characteristics of the stator current under the blade mass imbalance fault are obtained before and after considering the wind speed spatiotemporal distribution, then the simulation is carried out under the MATLAB/Simulink. Both the theoretical analysis and simulation results show that, considering the spatiotemporal distribution of wind speed and the influence of WS and TSE, the stator current will fluctuate under the blade mass imbalance fault. The fault characteristic frequencies include not only the blade rotating frequency but also the multiple rotating frequency of blade, but mainly the rotating frequency of blade and triple rotating frequency, wherein the rotating frequency is caused by the imbalance fault; the triple frequency fluctuation is caused by the equivalent wind speed.