Wind-Induced Response Of Long Span Transmission Line System

Transmission line system is the very important lifeline engineering system. Its damage can result in power interruption and fire disaster, and brings a great loss to the poverty. Long span transmission tower, as a kind of high-rise structure, is a key link in the whole system. In this paper, based on the Yamen 500kV transmission line system, the dynamic behavior and wind-induced response of transmission line system under stochastic wind load is discussed.Long span transmission system is a complicated system due to the nonlinearity of conductor line and the influence of insulator. Finite element method is a primary method in the analysis of nonlinear structure. In this paper, a new kind of curved cable element is used to simulate the transmission lines, nonlinear truss element that considers the effect of large displacement is used to simulate the insulator, and truss element is used to simulate the members of the transmission tower. In this way, the accurate spatial finite element model of the system is established. Nonlinear static analysis should be completed before the modal and dynamic analysis.Then through the modal analysis, the frequencies, vibration modes and damping ratio of the whole system can be achieved based on the deformed shape and inner force calculated by static analysis. The result is compared with those of another few computation models such as single tower, single cable, etc, and the interaction between towers and lines is presented. During the analysis of wind-induced response, traditional WAWS method is used to simulate the time-history record of fluctuating wind. This method is effective, simple and accurate.Through analytical studies of the dynamic behavior and wind-induced response of a transmission line system, some conclusion, which can be used for reference to practical engineering design, is drawn in this dissertation.