Vibration-Based Fingerprint Algorithm for Structural Health Monitoring of Wind Turbine Blades

Abstract

Monitoring the structural health of wind turbine blades is essential to increase energy capture and operational safety of turbines, and therewith enhance competitiveness of wind energy. With the current trends of designing blades ever longer, detailed knowledge of the vibrational characteristics at any point along the blade is desirable. In our approach, we monitor vibrations during operation of the turbine by wirelessly measuring accelerations on the outside of the blades. We propose an algorithm to extract so-called vibration-based fingerprints from those measurements, i.e., dominant vibrations such as eigenfrequencies and narrow-band noise. These fingerprints can then be used for subsequent analysis and visualisation, e.g., for comparing fingerprints across several sensor positions and for identifying vibrations as global or local properties. In this study, data were collected by sensors on two test turbines and fingerprints were successfully extracted for vibrations with both low and high operational variability. An analysis of sensors on the same blade indicates that fingerprints deviate for positions at large radial distance or at different blade sides and, hence, an evaluation with larger datasets of sensors at different positions is promising. In addition, the results show that distributed measurements on the blades are needed to gain a detailed understanding of blade vibrations and thereby reduce loads, increase energy harvesting and improve future blade design. In doing so, our method provides a tool for analysing vibrations with relation to environmental and operational variability in a comprehensive manner.

Accuracy Characterization of a MEMS Accelerometer for Vibration Monitoring in a Rotating Framework

“…A wireless vibration monitoring system based on acceleration measures in an operating wind turbine was proposed in Ref. [25], while in Ref. [26] a wireless inertial measurement unit capable of sensing angular speed and tri-axial accelerations was experimentally investigated on a 3 MW wind turbine.…”

The effect of damage position on Operational Modal Analysis of wind turbine blades for SHM

“…As wind turbine generators become larger and move farther off-shore, physical inspection, repair and maintenance on the one-side and cost of down-time on the other side take an increasingly bigger part of the Operating Expenses (OPEX) [1,2,3]. Many different techniques have been investigated in academia, a recent review has been given by Krause et al [4].…”