Long-Term Multiple Sensor Monitoring of a Hybrid Tower Wind Turbine – Lessons Learned

Wind turbines are usually designed for a lifetime of 20 years in Europe. A typical design of a wind turbine shows only little consideration for differences in location (flat areas, complex terrain), wind fields (rotating wind, upwind), or accessibility of the structure (off-shore, on-shore). Moreover, most wind turbines are typically equipped with only a few sensors that are used to control the turbine and record electrical and meteorological data. This makes it difficult to set up an efficient maintenance strategy to optimize maintenance intervals, the replacements of malfunctioning parts, the durability of the components, the cost of electricity, and to determine the remaining useful life. The authors are members of a group from the Technical University of Munich who have had the opportunity to work on several projects dealing with the improvement of monitoring systems and using a combination of wireless, wired, and other sensing techniques. It was the objective to obtain critical data at carefully selected points of the tower of a hybrid wind turbine out of pre-stressed concrete and steel. Automatic data recording, evaluation, and transmission techniques have been implemented to update material models in the frame of a digital twin of the turbine, identify icing on blades, optimize maintenance and operational parameters, and increase the overall sustainability of the turbine. The paper summarizes some of the findings from more than seven years of research.