Static And Dynamic Studies On Long-span Transmission Line System

Transmission line system is one of the crucial high rise structures, and it has been developed since last century in China. The progress trends for transmission lines in future are high rise, long span and high voltage. This paper mainly studies on static and dynamic characteristics for the 500kV Yamen long span transmission line system, which is designed and tested by our research group.Based on theories of nonlinear finite elements, several dimensional finite element models are established, including transmission tower models and other transmission line system models, with the conductor lines, insulators and elevators taking into account. Dynamic characteristics and coupling effect for these transmission towers, transmission lines and transmission line systems are analyzed. And the nonlinear static analysis for these models should be carried out before the dynamic analysis. Furthermore, the local deformation and the cross section arrangement for transmission towers are also discussed.According to the WAWS method, wind loads in time domain for Yamen long span transmission line system are simulated. Consequently, the wind-induced response in time domain for several transmission tower models and transmission line system models is studied, and the average value and variance of the wind-induced response under different load cases are achieved. Some valuable results are derived from the analysis of the response's power spectrum too. Then, the theoretical method and correlative actual criterions for the wind-induced vibration coefficient of transmission towers are introduced. According to different items for three actual criterions in China and results of wind-induced response in time domain for six different finite element models, nine sorts of wind-induced vibration coefficients for Yamen long span transmission line systems are obtained. Through the comparison, some rules for wind-induced vibration coefficients of long span transmission towers are concluded, and these results are also verified through the calculation of inner forces for transmission tower chords.