Dynamic characteristics of ice-shedding on UHV overhead transmission lines

Ice-shedding can cause violent oscillation of the lines, and make the conductors jump up and down. The dynamic effect of ice-shedding on transmission lines implies two categories of electrical and mechanical concerns. A 3-DOF (degree of freedom) dynamic model for multi-span lines was developed to calculate dynamic effects of ice-shedding on ultra high voltage (UHV) overhead transmission lines. The influencing factors were studied including the ice thickness, percentage of ice-shedding, span length, number of spans per line section, different elevation between suspension points, and nonuniform mode ice-shedding. Consideration of the ice-shedding problems is very important in determining the alignment of the conductors, the type of towers and the configurations of spans in UHV overhead transmission lines. The impact factor of static longitudinal imbalance tension changing to dynamic longitudinal imbalance tension can be confirmed as 1.8 through the massive computations, which meets the demand of projects.