Mechanism Analysis Of Wind-induced Collapse Of Ice-covered Terminal Tower Of Transmission Line

Electric energy as an indispensable core energy in people’s daily work and life,is not only an important foundation for industrial development,but also a basic guarantee for people’s life.As the main carrier of electric energy transport,the transmission tower-line system is very important for its operation stability and safety.The transmission tower-line system is a towering,long-span structure,stiffness and damping are relatively small,in extreme environment such as freeing and strong wind,line dancing is easy taking place,and even serious electricity accident such as disconnection and collapse may happen.This paper takes a 35 KV transmission line project as the background,modeling and analysis of the wind-induced collapse mechanism and its influencing factors of the tower-line system of the ice-covered terminal tower.The specific work is as follows:1.By comparing and analyzing the finite element of the Link element,Beam element and both Link and Beam hybrid element model of the transmission tower,and the most accurate hybrid modeling approach has been determined.On this basic,a reasonable finite element calculation model of the terminal tower-line system is been build,which comprehensive consideration of line’s initial shape and elastic boundary.Using modal analysis,the structure dynamic characteristic parameters of terminal tower and tower-line system are obtained.2.Considering the spatial coherence of fluctuating wind load on transmission tower and transmission conductor,the time-history curve of fluctuating wind speed according to Davenport spectral density was simulated based on harmonic superposition method.And according to the shape coefficient of the transmission tower and the aerodynamic coefficient of the ice-covered transmission line,the reasonable wind load of the terminal transmission tower of tower-line system is determined.3.Through transient response calculation or structure static calculation,the influence of parameter on the maximum equivalent stress of the terminal transmission tower of tower-line system is analyzed from the wind direction angle and the line strike angle.And the most dangerous wind direction angle condition and the most reasonable line direction are determined.4.Considering galloping effect of ice-covered conductor,taking pressure rod buckling failure or tension rod yielding as the dynamic failure criterion of transmission tower component,and simulate the entire collapse of transmission tower through transient analysis,revealing the collapse failure mechanism and influencing factors of the terminal tower-line system.