Size, shape and layout optimization of mono-mast guyed transmission line towers

Guyed lattice transmission line towers (TLTs) have been often used in transmission lines (TL) because they are light and easily adapted to flat terrains. Even so, a comprehensive literature review reveals that optimization studies on guyed structures are still incipient, with the few reported works emphasizing telecommunication masts. Unlike the latter, guyed TLTs must withstand asymmetric longitudinal loads scenarios originating from the conductors’ cables and ground wires, generating important torsion effects. Then, significant errors appear when equivalent linear models are adopted due to the nonuniform stayed cables’ loosening. Furthermore, it also leads to a much harder convergence of the nonlinear structural solution. Thus, this paper presents a novel approach for the simultaneous size, shape, and layout optimization of mono-mast guyed TLTs. The proposed framework integrates a proper layout optimization scheme for handling the staggered bracing configuration (typically found in lattice masts), an adaptive control strategy in both predictor and corrector stages to efficiently solve the nonlinear solution, and a parallel computing procedure. In addition to the tower size/shape/layout, the diameter and slope of the stayed cables are also taken as design variables. The optimization is performed using the Backtracking Search Algorithm (BSA) due to its flexibility to deal with discrete or mixed (discrete-continuous) variables present in the problem. The numerical procedure is assessed in two real-world guyed TLTs, and the final results reached saving costs up to 8.16% when compared to its original design.