Numerical Simulation Of Ice-shedding And Wire-breaking On Transmission Line System

The oscillation of transmission line often occurred in Ice-shedding and Wire--breaking situation. It may deduce line trip and cause flashover between different phase conductors and even collapsing of transmission tower, which may in turn severely imperils the safe operation of the high voltage transmission line. Therefore, the study of them behaves great significance in power supply engineering. In this paper a finite element model of a practical transmission line was established by ANSYS, the dynamic characteristics of transmission line system, static response when icing, ice-shedding and wire-breaking problem were studied.A form-finding method was proposed while solving the form-finding problems in cables by nonlinear finite element method. This method is convenient, fast and effective when compare with the theoretical calculation. The static response characteristics of several conditions with different ice thickness, span and the elevation between suspension points were analyzed. And the dynamic characteristics of a single tower, cables and tower-line system were studied.This paper focuses on the problem of ice-shedding amplitude, getting the amplitude characteristics of ice-shedding on transmission lines, and revealing the influence of various parameters on the he amplitude of ice shedding. Several conclusions can be drawn according to the simulation results: the amplitude of ice shedding increases faster and faster with the ice thickness, percentage of ice-shedding and conductor stiffness increasing; the number of spans per line section within a certain range of the amplitude of ice-shedding is larger, the impact tends to be stable when the number more than a certain file; these factors of the elevation between suspension points and insulator have a little effect on amplitude of ice-shedding; with different type of ice-shedding the amplitude of ice-shedding has a great change; the wind load has a great impacts on the horizontal displacement of transmission line;In this paper,percentage of ice-shedding on the jump amplitude maximum effect,the interaction between percentage of ice-shedding and type of ice-shedding with minimal impact to the amplitude.Finally, the displacement and internal force of the tower adjacent to the wire-breaking span were studied. The study found the impact of wire-breaking to the tower mainly in its head and neck, and some bars transient impact load is three to four times the static load.