Study of Dynamic Impacts on Transmission-Line Systems Attributable to Conductor Breakage Using the Finite-Element Method

Abstract

The residual static load (RSL) is defined in the ASCE 74 standard as the loading criteria for a broken wire condition. However, a transmission line designed on the basis of the RSL may be unsafe because the RSL takes no account of the dynamic impact effect. This study develops a general finite-element analysis procedure to resolve the conductor breakage problem and to determine the broken wire load (BWL) for the transmission-line design. The developed procedure can account for the impinging and friction effects between the broken conductor and the ground. A three-span transmission line with the line configurations previously tested at full-scale was examined, and the results showed that the developed procedure could predict a realistic time history of responses. The developed procedure was then applied to a nine-span transmission line, and the results showed that the peak BWL was significantly greater than the RSL, indicating that the peak BWL instead of the RSL should be used to check the extreme load case for the conductor’s breakage condition.