Dynamic responses of the conductors in transmission lines under two typical impact loads

Impact loads from ice shedding and broken conductors are common for transmission lines in accreted ice zone, which can bring threaten to the safe operation of the transmission lines. Dynamic analysis of the conductors in transmission lines under two typical impact loads were carried out. Firstly, a finite element model of seven span conductors in transmission line was established in general software ANSYS. Secondly, a time history of the input loading was proposed for the ice shedding load case. Dynamic responses of jumping heights and the reaction forces at the end of insulators were calculated by the implicit dynamic analysis. Some variables were considered in the ice-shedding simulations that include thickness of the accreted ice, length of the ice-shedding span as well as elevation difference. Influences of all the variables on the dynamic responses under ice shedding were studied. Thirdly, the broken load case can be realized by birth-death element method in ANSYS. Stiffness of the broken conductor or insulator element was changed to be a near zero value in a very short time. Dynamic responses of displacements at the broken points, tension forces of the conductors and the reaction forces of the insulators were obtained. Lastly, based on the analysis results, the impact factors under ice shedding and broken conductor load cases were determined, which provide important reference for the design of transmission lines in accreted ice zone.