With the growing trend toward large-scale wind turbines, the loads acting on blade root bolts are becoming increasingly severe. Real-time awareness of their service condition is crucial for ensuring reliable operation of wind turbines. In this paper, a theoretical analysis is first conducted on the load transfer of the wind turbine pitch system and the load characteristics of blade root bolts, and a correlation equation between the pitch motor current and the bolt load is established. Subsequently, a time-domain characteristic analysis of the pitch motor starting current is carried out based on field-measured SCADA data from a wind farm, and the differences in the pitch motor current characteristics before and after blade root bolt fracture are compared. Finally, an electromechanical coupled simulation model incorporating vector control of the pitch motor and load transfer is built using MATLAB /Simulink, and the time-domain characteristic values of the pitch motor starting current under conditions with and without blade root bolt fracture are analyzed. The results show that the fracture of blade root bolts in wind turbines leads to load redistribution and changes in connection stiffness, which consequently results in larger time-domain characteristic values of the pitch motor starting current compared to those under the intact condition.

Yaowei Song, Shuyi Yang, Lipeng Peng, Tieqi Zhou. Correlation Analysis between Load Characteristics of Wind Turbine Blade Root Bolts and Pitch Motor Current. Academic Journal of Engineering and Technology Science (2026), Vol. 9, Issue 4: 1-12. https://doi.org/10.25236/AJETS.2026.090401.

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