Overhead transmission line for the measurement of real loadings on high-voltage conductors

Overhead transmission line for the measurement of real loadings on high-voltage conductors

Source: BAM, Division Buildings and Structures

Aerodynamic damping is a decisive parameter influencing the dynamic response of overhead transmission line conductors. Methods of how to account for the effects of aerodynamic damping differ significantly and so might do the results. In this work, the source of aerodynamic damping being the result of the relative velocity between the structure and wind flow will be revised. Based on wind tunnel tests and validated by simulations, the differences of linear movement compared to a pendulum movement of a sagging cable are shown. The reasons for that Deviation are the large deflections, resulting in a movement non-parallel to the acting wind flow. For analysis in frequency domain, it is not possible to incorporate aerodynamic damping implicitly by fluid structure interaction. If the dynamic movement can be linearized at a working point of the mean deflection, a modification to the linear approach is suggested. This approach is validated by simulation with a finite element model of an existing overhead transmission line, calibrated with full scale measurements. Aerodynamic damping is incorporated in time step analysis by Rayleigh damping and modal damping. The differences between both approaches are emphasized and modal damping is shown to be the most adequate

Aerodynamic damping of nonlinear movement of conductor cables in wind tunnel tests, numerical simulations and full scale measurements
Dominik Stengel, K. Thiele, M. Clobes, Milad Mehdianpour
Journal of Wind Engineering and Industrial Aerodynamics, Volume 169, October 2017, Pages 47-53
BAM Department Bauwerkssicherheit, Division Buildings and Structures