Health Assessment of Operational Wind Turbine Infrastructure Based on Wavelet Packet Energy Spectra

In response to the issue of foundation ring and concrete cracking in operational wind turbine foundations, this study proposes a novel method for health monitoring and damage assessment of foundation structures utilizing the wavelet packet energy spectrum. The characteristics of the damaged wind turbine foundation are extracted by analyzing its vibration velocity response signals. The degree of damage then is determined based on the wavelet packet energy spectrum, energy ratio variation deviance (ERVD), and energy ratio variation variance (ERVV). Field tests were conducted at a wind farm in Zibo, China, to validate the effectiveness of the proposed method. The results demonstrated that vibration spectrum analysis of the wind turbine foundation can reflect the impact of damage on vibration frequency. The vibration frequency at the damage location decreases, with a significant absence of low-frequency components. The energy index is particularly effective in identifying damage between the wind turbine foundation and the foundation ring. Larger changes in energy amplitude indicate severer damage. Different damage indicators exhibit different degrees of effectiveness in identifying damage in wind turbine foundations. ERVD is highly sensitive to foundation damage and demonstrates substantial amplitude changes, whereas ERVV has smaller amplitude changes and is less effective in detecting damage. The findings suggest that the proposed method provides a reliable approach for assessing the health of wind turbine foundations by highlighting areas of damage and their severity.