Structural health monitoring of the support structure of wind turbine using wireless sensing system

The wind turbine heavily depends on the success of the support structure to resist the complicated environmental loading, especially for the offshore wind turbine. How to manage these wind turbines and monitor the structural safety becomes an urgent and important issue today. To monitor the support structural safety of wind turbine, a good understanding of the structural dynamic behaviors of wind turbine is preliminary requirement. Due to the complicate dynamic behaviors of realistic wind turbine which includes the effects of the soil-structure interaction (SSI), the machine operation loading, the wind interaction, etc., both the numerical model study and the system identification are required to clarify these complicated structural behaviors. In this study, a wireless sensing system, NTU-WSU, is installed in an on-shore large wind turbine (GE 1.5MW) to collect the structural responses, and the system performance of the proposed NTU-WSU was also evaluated in this study. Three measurement layouts and two operational scenarios (operating and stop states of the wind turbine) are considered in this study to clarify the complicated structural dynamic behaviors. Two system identification approaches are adopted in this study to extract and verify the structural dynamic features, direct Fourier spectrum observation method and frequency domain decomposition (FDD) method.