Evaluation of Dynamic Characteristics and Wind Resistance of 220 kV Dual-Loop Typical Angle Steel Transmission Tower

The transmission tower is a kind of wind-sensitive structure with the characteristics of high self-weight, structural flexibility and small damping, and is sensitive to wind load excitation. The wind load in the typhoon-prone areas in the southeast coast is an important cause of tower collapse and accidents. In order to improve the safety and reliability of transmission lines in the southeast coastal areas of China, it is particularly important to reasonably evaluate the wind resistance performance of transmission towers in this area. In this paper, the dynamic characteristics analysis, wind-induced vibration response analysis and wind-resistant performance evaluation of a typical transmission tower are carried out based on a new 220 kV double-circuit transmission line in the coastal area of Fuding, Fujian Province. Firstly, the dynamic characteristics of the transmission tower were tested on site to test the response of the transmission tower under natural excitation, and the dynamic characteristics parameters such as the frequency and damping ratio of the transmission tower are identified by the random subspace method; Secondly, the finite element calculation model of the transmission tower is established by using ANSYS software. Through theoretical analysis and field measurement of the dynamic characteristics of the transmission tower, the vibration characteristics of the tower are further understood and mastered, and the correctness of the finite element model is verified; Further, according to the existing specifications, the static wind load analysis of 0°, 45°, 60° and 90° and the wind vibration response analysis with wind speed return period of 30 years, 50 years and 100 years are carried out for the transmission tower, and the maximum compressive stress value of the main material of the transmission tower under the static and fluctuating wind load is obtained. On this basis, the wind resistance performance of the transmission tower is evaluated by the tower top offset ratio, the pole bending ratio and other evaluation parameters. The results show that this method can effectively evaluate the wind resistance of the transmission tower with the wind speed return period of 30 years, 50 years and 100 years, and the conclusion that the wind resistance design of the transmission tower is relatively safe is obtained. The research and related conclusions have important reference value for the wind resistance design and wind resistance performance evaluation of transmission towers in the future.