Search

An overhead transmission line system is a typical wind-sensitive structure with high flexibility, light weight, and low structural damping. Wind-induced dynamic reaction of the transmission line system is a determining factor in structural design of the supporting tower. In this study, we employ a closed-form solution and a series of wind tunnel tests to investigate three-dimensional dynamic reaction of transmission lines bundled with an insulator in three types, including I-type, V-type, and strain-type. The response comprises the background and resonant component. It is found that the background component constitutes a major part of the response, and the resonant component is closely related to the first symmetric out-of-plane mode. Furthermore, the closed-form solution is discussed and validated by the aeroelastic wind tunnel testing in the frequency domain. Based on the experimental data, this study provides a theoretical method for predicting wind-induced loads on transmission tower structures. [ABSTRACT FROM AUTHOR]

Downbursts wind are believed to be responsible for most of weather-related transmission line failures worldwide. Based on a theoretical model of a hinged single-span transmission line structure under moving downbursts, this paper studies downburst -induced vibration of a multi-span transmission line-insulator system (MSTLIS). Firstly, a nonlinear analytical framework for quasi-static responses of the MSTLIS under moving downbursts is established, and linearized equations of the MSTLIS under moving downbursts with time-varying mean wind speeds are derived. Then, the influence line functions of the insulator tension and displacement of the MSTLIS are derived, based on which the quasi-static responses of the MSTLIS under fluctuating wind is calculated. A case study on a six-span transmission line-insulator subsystem is conducted. The proposed nonlinear analytical model and the approximate linearization approach is verified by finite element model (FEM) results. The proposed analytical framework with linear approximation is accurate and more efficient than FEM, and hence has a great potential for real application. • An analytical framework for quasi-static responses of the transmission lines under moving downbursts is established. • Approximate linearized longitudinal stiffness is used to develop a more efficient tension under time-varying mean wind. • The linearized influence line functions of the insulator tension and displacement under fluctuating wind are derived. • The proposed analytical framework with linear approximation is accurate and more efficient than finite element analysis. [ABSTRACT FROM AUTHOR]

A full aeroelastic model with one tower two lines to simulate electrical transmission tower-line system was established. Displacements and accelerations of the aeroelastic model of the tower with and without lines under various wind speeds were investigated through boundary layer wind tunnel tests, and the maximum wind loads on, and wind-induced destroyed mode of, the tower-line model were also observed. Meanwhile, the static and dynamic loads on electrical transmission tower transferred from lines were acquired by measuring the strains of the insulators at the ends of lines. The effects of coupling between electrical transmission tower and line on wind-induced vibrations of electrical transmission towers were investigated, and the pattern of wind induced responses along with wind speeds, as well as the characteristics of spectra of wind induced dynamic responses, of the aeroelastic model of the tower with and without line were analyzed. The experimental results indicate that the effects of coupling between transmission tower and line on wind-induced responses of the tower, as well as the across-wind vibration of the tower, must take into consideration in the wind-resistant design of electrical transmission tower; and the reinforcement at the weak parts of electrical transmission tower could effectively increase the survival ability of the tower under strong wind. [ABSTRACT FROM AUTHOR]