Comparison of Observed and Simulated Galloping Responses of a Four-Bundled Conductor Under Wet Snow Accretion

Field observations of four-bundled conductors have been carried out at the Kushiro test line since 2014 to investigate the galloping characteristics caused by wet snow accretion on overhead transmission lines. On January 12, 2022, a large galloping was observed at this site. It was seen that the conductors mainly vibrated in the vertical two-loops/span mode coupled with the horizontal and torsional modes. The maximum total amplitude reached approximately 5.8 m in the vertical direction. Numerical simulation is an effective method for estimating the galloping response amplitude of full-scale overhead transmission lines; however, the simulated response amplitude is highly dependent on the input conditions, such as snow accretion shape and wind speed. Therefore, this study conducted a parametric analysis to evaluate the sensitivity of the response amplitudes to the input conditions by varying the snow accretion shape and its development angle in addition to wind speed. The results of the analysis under the snow accretion conditions closest to those observed on January 12, 2022, were found to approximately reproduce the observed response amplitudes.