The impact effect of power transmission tower-line due to broken wire of transmission line is studied in this paper.Equations of dynamic equilibrium of structure before and after broken wire are given.The tower

the isolator and the transmission line are simulated by the beam element

truss element and catenary cable element

respectively.Considering the geometric nonlinearity of transmission line

the three-dimensional finite element model of the power transmission tower-line system is created based on a practical engineering and the dynamic characteristics of tower are calculated.Based on analysis method and cases

the impact effects of power transmission tower-line system under different cases of broken wire are researched

respectively.The results show that the impact effect of ground line is very small

and different combinations of broken wire of the conductor should be considered.The impact value under broken wire of two conductors is close to the safety factor of design.So the impact effect of power transmission tower subjected to broken wire can not be ignored.