Analysis Of Vibration And Aerodynamic Characteristics Of 500kV Tower Line System Under Mountain Pass Terrain

The tower line system in the micro topography of the pass was easily affected by the extremely complex environment,which might cause the collapse of the transmission towers.Therefore,it is of great engineering significance to study the dynamic characteristics of transmission tower line system in a complex environment under the micro topography of pass.In this paper,the vibration and aerodynamic force of the tower system under the micro topography of a mountain pass were analyzed and studied under the background of the wind deflection trip accident of a 500kV high voltage transmission line in Yunnan province.1)3D entity modeling was carried out for the micro-topography data of pass collected by GPS;The three-dimensional wind field characteristics of micro topography of mountain pass were studied by CFD(Computational Fluid Dynamic)method.The results showed that when the wind was directly opposite the pass,the wind acceleration effect was obvious in most areas of the micro topography of the pass,especially at the position of Tower 46#at the back of the pass,the wind speed acceleration ratio reached 1.32.2)Using ANSYS software,the finite element model of three towers and two lines in the wind-deflection trip accident section of a 500kV HV transmission line in Yunnan was established.Firstly,wind and rain excitation analysis is carried out to obtain the displacement response of transmission wires under different rainfall conditions.It is found that when the inlet wind speed is 25m/s and the rainfall intensity is rainstorm,the displacement response of the wire is the most intense,and its displacement is 29.1073m.Then the modal analysis of the three-tower and two-wire finite element model is carried out.It is found that in the first several vibration modes,the vibration of the three-tower and two-wire finite element model is mainly manifested as the transmission wire moving sideways along its vertical direction(in the same direction or in the opposite direction).With the increasing of the order,The vibration pattern begins to show a mixed state of the transmission wire moving sideways in its vertical direction(same or opposite direction)and twisting in one of its directions.3)The Fluent module is used to model the two-split wire under the conditions of non-ice-covered,crescent ice-covered and rain-covered,and to conduct aerodynamic analysis on it.The results show that the aerodynamic force of the leeward conductor is more complicated than that of the windward conductor under non-icing condition due to the influence of vortex shed.By analyzing the variation curve of the aerodynamic coefficient of the leeward conductor covered with crescent,it is found that the abrupt change range of the aerodynamic coefficient of the leeward conductor ranges from 80° to 110°.By analyzing the curve of the aerodynamic coefficient of the leeward conductor with the upper rain line,it is found that the abrupt change range of the aerodynamic coefficient of the leeward conductor with the dip Angle of the rain line is 40°～60°.