Study on dynamic characteristics and wind-vibration control of transmission tower considering local damage and destruction

As existing transmission lines gradually approach their service life, health monitoring studies of in-service transmission towers are becoming increasingly important. In this study, relying on the 110 kV transmission line project of Neihuang Dichu to Er'an in Anyang, Henan Province, China, a refined finite element model of the transmission tower structure was established, and the accuracy of the numerical model was validated based on the health monitoring data of the actual engineering structure. Damage and destruction analyses of transmission tower structures considering vibration modes and frequencies were carried out, and the influence of local damage on the vibration reduction effectiveness of controlled structures under wind loads was discussed and analyzed. The results showed that the vibration mode of the local damage model was shifted along the damaged part, and its frequency changed within 15 %; in contrast, the dynamic characteristics of the local damage model changed more significantly. With the vibration mode as the judgment basis of the structural state, the obvious difference can be observed when the structure undergoes local damage, and the vibration mode should be used as the basis for determining the specific damage site of the transmission tower in the actual project. The adopted TMD can effectively reduce the dynamic response of the transmission tower under different wind attack angles and wind speeds, and its vibration reduction effectiveness performed the worst due to the significant change in the dynamic characteristics of the tower leg damage model, resulting in the detuning of the TMD.