Analysis on dynamic responses of transmission tower-line system under ice shedding

A three dimensional finite element model of tower-conductor-ground wire-insulator system was established in ANSYS,and the dynamic responses of ice shedding under different cases were analyzed for transmission tower-line system.Many factors were considered in the ice shedding simulating analysis,which includes tower-line coupled effect,the quantity and location of conductor phases,thickness of the accreted ice,length of span as well as elevation difference.Influences of all the factors on the dynamic responses of jumping heights,loads at the end of insulator and the forces of transmission tower were mainly studied.Ice shedding simulating analysis of an actual 500 kV transmission line section which happened ice disaster in 2008 was completed,and the results show that stress ratios of the members at tower head under design ice thickness will exceed the limited values when the amount of ice shedding is much larger.For the ice shedding at the top phase conductors,the jumping height and unbalanced tension at the end of insulator can be reduced obviously by applying triangular phase to phase spacers,and the tower is in safe state under design ice thickness.As to prevent ice shedding accidents,phase to phase spacers should be used,and the weak members at tower head should be strengthened according to the calculated load values at the end of insulators.