Simulation Analysis On Dynamic Safety Distance Of Crossing Line Under Galloping Condition

The flashover characteristics of transmission line galloping are of great significance for the design and safe operation of complex overhead lines.Ice galloping of crossing lines will not only affect their own operation,but also affect the safe operation of high-speed,railway and transmission lines.In this paper,a finite element analysis model of tower line system is established to simulate the galloping condition of conductor and ground wire.The dynamic displacement response of conductor and ground wire under different galloping conditions is calculated,and the dynamic variation law of safe galloping distance is emphatically discussed.The main contents of this paper are as follows:Based on the Kaimal spectrum of power spectrum changing with height,the random fluctuating wind field is simulated,which is superimposed with the average wind speed of galloping,and then the instantaneous wind speed time history curve of galloping can be simulated.The galloping wind load across the transmission line is applied by using the galloping dynamic control equation.The galloping condition of the transmission line is numerically simulated based on ANSYS finite element software,and the correctness of the simulation method is verified.A new method is proposed to calculate the clearance between conductors and ground wires,which is the key segment method.The method can obtain the node number and position information corresponding to the minimum clearance while calculating the dynamic clearance of the ground wire.Combined with the analysis process of the ground wire flashover,the safety factor is introduced to evaluate the flashover risk of the crossing line under the dancing condition,and finally find the location of the flashover and the corresponding information of the conductor and ground wire.The dynamic characteristics of galloping across the line are analyzed.Based on the aerodynamic parameters of crescent iced conductor,the displacement response of crossing line under galloping condition is numerically simulated,and the frequency spectrum is analyzed.Based on the flashover analysis process of conductor and ground wire,the influence of the change of external environmental factors(wind speed,icing thickness)and the structure of the line itself,including the change of line crossing angle and span,on the safe distance is analyzed.