Numerical simulation on jump height of transmission line subjected to ice-shedding with different time intervals

The vibration of ice-shedding on overhead transmission lines will result in serious damage to tower-line system. In order to reveal the effect law of the different time parameter on the jump height of iced overhead lines after ice shedding, the conductor-insulator coupled finite element model was established, and the additional force method was employed to simulate the process of ice-shedding from overhead transmission lines, then the values of jump height were obtained for simultaneous total-span ice-shedding, unzipping ice-shedding, and assembling ice-shedding. Results from this study showed that, the difference between numerical simulation result and formula calculation result was negligible for simultaneous total-span ice-shedding. The dynamic response of unzipping ice-shedding is close to static unloading when the velocity was lower than 20m/s, the jump height was far less than calculated value by empirical formula, but the jump height of unzipping ice-shedding is close to simultaneous total-span ice-shedding effect when the velocity of ice-shedding is higher than 50m/s. The minimum jump height occurs when ΔT=T/2 for one-span assembling ice-shedding; and the maximum jump height occurs when ΔT=T/8, which may slightly greater than simultaneous total-span ice-shedding because of conductor coupling effect.