Detailed Design of Lattice Tower for Low Speed Wind Turbines

This study presents the design of a lattice tower for wind turbines with a downwind rotor configuration, intended for operation in low-intensity wind conditions (Class III-B, according to IEC 61400-1). Developed as part of the ABV/Furnas project, the analysis outlines the criteria used to define the optimal tower typology, considering structural, aerodynamic, and economic factors. A key challenge in downwind rotor turbines is the wake generated by the flow around the tower, which can negatively affect rotor performance. To address this, a lattice tower with aerodynamic-profiled members was selected. This solution not only reduces aerodynamic interference but also lowers manufacturing, transportation, and assembly costs. The study demonstrates the feasibility and innovations of this approach. It highlights how lattice structures reduce aerodynamic impact, enhancing rotor efficiency. The analysis covers essential structural and geometric parameters, including weight, wind blocking area, ground loading, and their influence on foundation costs. Additionally, the effect of tower geometry on its natural vibration frequency is examined to prevent resonance and ensure long-term structural stability. Various lattice tower configurations are compared to conventional tubular towers, assessing their technical performance. Logistical constraints – such as transportation feasibility, on-site assembly, and limitations of the Brazilian steel market – are also evaluated, ensuring the practicality and cost-effectiveness of the proposed design for deployment in Brazil.