The Simplified Analysis Method Of Transmission Tower's Stiffness And The Response Research On Galloping Transmission Line

Transmission tower is tall-flexible structure among the system of transmission tower-lead, the disposal of the bars and its cross-section affect the stiffness of the transmission tower. The spans of transmission line exceed 100m,even measured up 1000m, the transmission line will gallop with the effects of winds, and generates huge fores to the transmission tower, bringing unexcepted respondings to the transmission tower and lead.In the paper,the theoretical expressions of the Axial stiffness,Bending rigidity and Torsional stiffness are established using Slice-truss method, analysing the influences of the parameters in the expressions using numerical methods,comparing the simulation results with the FEM result. then the critical wind of galloping, the amplitude of galloping and the relation between the galloping and the angle of attacking wind are derived; The dynamic load of the galloping transmission line under Den Hartog galloping is established in the paper; through the analysis of the classic transmission tower, including the responds of displacement and the effects of the insulater to the displacement. The following conclusions are derived:1,The outcome of quivalent axial stiffness in the paper is close to the truss element FEM model;the quivalent axial stiffness increases with the Tower-leg cross-sections; the quivalent axial stiffness increases with the belly bar cross-sections nearly linearly; the quivalent axial stiffness decreases with the length of winding bar increasing when the hight of the tower section is setted. The outcome of quivalent bending stiffness in the paper is close to the beam and truss elements FEM model; The quivalent bending stiffness increases with the Tower-leg cross-sections; the quivalent axial stiffness increases with the belly bar cross-sections nearly linearly; the quivalent bending stiffness decreases with the length of winding bar increasing when the hight of the tower section is setted. The quivalent torsional stiffness has no ralation with the Tower-leg cross-sections; the quivalent torsional stiffness increases with the belly bar cross-sections nearly linearly; the quivalent torsional stiffness decreases with the length of winding bar increasing when the hight of the tower section is setted.2,The transmission line gallops under small angle of attacking wind (about 20 degrees to 30 degrees); when the wind load is small,the dynamic load of the galloping change slowly; the dynamic load of the galloping increases with the wind increasing.3,The X-displacement of the suspension point beteewen insulater and transmission line is composed deformantion of insulater and its pendulum movement along transmission line direction, and the latter share takes predominant part; the Z-displacement of the suspension point beteewen insulater and transmission line is constituted the deformantion of insulater mainly.