Structural analysis of steel towers used in power transmission lines subjected to wind induced dynamic actions

Resumo

The lattice steel towers have been widely used as supports for power transmission lines becoming
essential elements since their stability contributes to a better functioning and electrical safety of the transmission
systems. Although the main loading applied to this type of structure be produced by the wind acting dynamically
on the elements of the transmissions system (conductors, shield wires, insulators and steel towers), in the current
design practice the dynamic structural behaviour of the structural system (towers-conductors) is not considered.
Therefore, the main objective of this investigation is to develop an analysis regarding the behaviour of power
transmission lines when subjected to wind dynamic loadings, having in mind the assessment of the forces and
displacements of the steel towers of the system. In this research work, a power transmission line, composed by the
main tower, two adjacent towers, conductors, shield wires and insulators was studied based on a finite element
modelling, considering the wind non-deterministic dynamic characteristic, where the wind loads were modelled
by an aleatory process based on their statistical properties. The results obtained along the analysis have shown
relevant quantitative differences associated to the forces and displacements values when the structural response of
the investigated power transmission line was calculated based on a static analysis and a dynamic non-deterministic
analysis.