Limit State Evaluation for Transmission Tower-Line System

The physical infrastructure of the power systems, including the high-voltage transmission towers and lines as well as the poles and wires for power distribution at a lower voltage level, is critical for the resilience of the community to avoid power outages under the extreme weather related loads. In the current engineering practices, single circuit lattice steel towers linked by transmission lines are widely used to form power transmission systems. This study is to develop a limit state evaluation method for typical transmission tower-line system subjected to strong wind loadings. Wind tunnel experiments were carried out to obtain the drag coefficients for different panels of the transmission towers as well as for the transmission lines. Incremental dynamic analysis (IDA) is carried out to find the capacity curve for the transmission tower-line system. The probabilities of failure are evaluated based on two predefined limit states. The results show that the uncertainties from meteorology have considerable influence on the reliability of the transmission tower-line system.