A novel method for frequency analysis of a small wind turbine with tubular guyed tower: An experimental evaluation

The present study sets out a novel methodology for the theoretical and experimental analysis required to find the natural frequencies of a small wind turbine with a guyed tower. These frequencies may cause resonance phenomena when occurring close to each other. These phenomena require precise mathematical models and experimental analysis to facilitate structural design calculations. The method uses a life-sized commercial turbine mounted on a fold-down guyed tower, the Rayleigh-Ritz numerical method, vibration modes, blade frequency, and cable stiffness. In addition, cable stiffness value depends on various factors, such as diameter, longitude, and materials. The results reveal that it is possible to shift the fundamental frequency of the cable and its harmonics. The cable is the main element that may cause resonances in other elements of the small wind turbine with a tubular guyed tower due to the range of frequencies that can be adopted depending on the cable tension. Finally, the results show a reasonable concordance between the values for the natural frequencies calculated by the mathematical model and the experimental values, obtaining an error of lower than 3.43% for the fundamental frequency system.