A Numerical Approach to Reproduce Subspan Oscillations and Comparison With Experimental Data

Subspan oscillations is a well-known phenomenon in high-voltage and ultra-high-voltage transmission lines. It occurs on conductor bundles and it is due to the effect of the wake produced by the windward conductor on the leeward one. For this reason, the phenomenon is also classified as wake-induced oscillations. The oscillations are characterized by a frequency in the range 0.5-3 Hz, which corresponds to the mode of vibration of a section of conductor between two spacers, with an antinode at mid-subspan. In this paper, an overview of the numerical models adopted for the evaluation of subspan oscillation is provided. Moreover, a summarized description of wind tunnel tests was performed in Galleria del vento of Politecnico di Milano. Finally, a numerical experimental comparison aimed at validating the numerical model toward wind tunnel tests and field tests is reported and commented.