A study of galloping analysis of ice-accreted transmission line considering unsteady aerodynamic forces

In this study, the effect of unsteady aerodynamic force of ice-accreted transmission line on galloping analysis is investigated. First, unsteady aerodynamic coefficients of ice-accreted single conductor predicted by DES are validated by the wind tunnel test and verified by the galloping analysis based on the measured unsteady aerodynamic coefficients. The galloping analysis for ice-accreted 4-conductor transmission lines are then performed using steady and unsteady aerodynamic coefficients of single conductor, respectively. As a result, hysteresis of unsteady aerodynamic coefficient shows good agreement with the experiment. The mechanism of hysteresis is explained by the difference of pressure distribution on the ice-accreted conductor between positive and negative torsional directions. The galloping analysis using the unsteady aerodynamic forces improves the amplitudes of galloping predicted by the conventional quasi-steady approach.