DYNAMIC IMPACT EFFECTS ON TOWER-LINE SYSTEM DUE TO ICE-SHEDDING

Ice-shedding from overhead transmission lines will result in the dynamic impact effects on the conductors, shield wires, isolators, members of the tower and the whole tower. Finite element method is employed to construct the tower-line model and simulate the phenomena of ice-accreting and ice-shedding. Then the responses of the tower-line system due to ice-shedding are obtained. Results from this study show that, ice-shedding from conductors causes low-frequency vibration of the conductors and large-amplitude oscillation of the isolators. Many members of the tower experience high peak impact stresses. At the same time, ice-shedding causes a significant increase of the base shears and base moments of the transmission tower. The impacting effects of the transmission-tower line system due to ice-shedding may increase with the decreasing distance between the tower and ice-shedding span.