Abstract: Transmission tower is an important load-bearing facility of transmission line, and its safety is directly related to the normal operation of the national grid and transmission line. Wind-induced response of transmission towers is mainly studied by field measurement, wind tunnel test and numerical simulation. With the development of computer technology and numerical methods, numerical simulation analysis on wind-induced response of transmission towers begins to be widely adopted and significant achievements were gained. Wind load model and structure model are established, then the structure dynamic response characteristics and the corresponding wind vibration control method are studied in related numerical simulation research, so progress of wind-induced response numerical simulation research of transmission tower is summarized from wind load model, structure model and dynamic response characteristics and wind vibration control research in this article.
The mean wind and fluctuating wind model of wind field in the ground layer is the basis of building structure wind load. The wind speed profile model used for the mean wind mainly includes exponential and logarithmic wind speed profile model, while the fluctuating wind is mainly simulated according to turbulent wind power spectrum. Under different extreme weather conditions, wind field shows different characteristics from normal wind. The corresponding mean and fluctuating wind models need to be further studied according to the actual situation. The wind load of transmission tower also needs relevant structural parameters, in which the wind resistance effect of tower structure and the shielding effect between tower components can be studied by flow field simulation.
When building the transmission tower finite element model, the transmission tower can be regarded as the rigid frame structure and the truss-beam structure, while the error of simulation by using the truss model is large. In addition to wind load and other external environmental loads, the influence of transmission line on tower structure should also be considered, so the tower-line coupling system should be established to simulate the actual structure characteristics of transmission tower. In the process of building the finite element model of tower-line system, the catenary theory and the horizontal tension of conductor can be used to model and shape the conductor.
Based on the wind load model and the structural model, the wind-induced response of transmission tower can be analyzed. The dynamic characteristics of the structure have important effects on the wind-induced response, and the effect of the conductor on the tower makes dynamic characteristics of tower-line system more complex. For the wind load of tower under different wind direction, the relevant codes have corresponding calculation coefficient and distribution coefficient. For the tower-line coupling system, the wind direction has more significant effects on the wind-induced response.
According to whether external energy input is needed, wind-induced vibration control can be divided into active control, passive control and hybrid control. So far passive control, especially tuned mass damper, is still the main method for wind-induced vibration control of transmission tower. The natural frequency of damper should be consistent with the natural frequency of tower, then the wind-induced vibration control works best. However, the optimization of wind-induced vibration control is more complicated due to tower-line coupling effect.
Besides, future research direction was prospected. Further research on wind field characteristics of special weather, development of more reliable finite element modeling methods, further study of tower torsional and along-line response characteristics, and optimization of TMD design parameters and layout should be important research directions in the future.