Modeling Ice Shedding Propagation on Transmission Lines with or without Interphase Spacers

Ice shedding propagation on a single conductor and on a circuit of three conductors in a vertical configuration where conductors are linked with interphase spacers was modeled numerically. Several concentrated loads acting along the loaded span modeled the ice, and the shedding propagation was then simulated through the removal in a defined sequence of these concentrated loads. The model determines conductor displacement and the variation of conductor tension during the vibration following ice shedding propagation; and, thus, it predicts conductor rebound height, tension peak, and to what extent the conductor clearance is reduced during vibration. Ice shedding propagation on the full-scale test line of Hydro-Quebec was considered, and the model was validated by comparing simulation results to former experimental observations. The results show that the application of spacers reduces the severity of vibration considerably, and consequently increases the conductor clearance and reduces the risk of flashover. The dynamic effects of different shedding processes were also compared. The rebound height is the greatest for a single conductor when ice detachment propagates along the conductor, but then ice falls suddenly as a big chunk. However, the consequences of sudden detachment and shedding are obtained as the most severe when conductors are linked with spacers.