Experimental investigation of self-damping characteristics of the ACSR Beresford and TERN transmission line conductors using log-decrement and quality factor methods

Abstract

This work considered the experimental investigation of self-damping characteristics of ACSR Beresford and TERN transmission line conductors using the free and forced vibration techniques. When subjected to a load, self-damping is the power dissipated per unit length of the conductor as it vibrates. ACSR Beresford and TERN conductors are the two most commonly used conductors in the South African transmission network. The paper has revealed that for all the tests, the damping factors for the forced vibration on the TERN conductor was ζ ≤ 0.0307, and for the free vibration was, ζ ≤ 0.057, whereas the damping factors for the ACSR Beresford (forced vibration) were found to be ζ ≤ 0.0103, and for the ACSR Beresford (free vibration) were found to be ζ ≤ 0.056.The damping factors obtained in both conductor-tests were not sufficient to suppress Aeolian vibrations. Results obtained by Mokeretla (2011), that the internal self-damping of TERN transmission lines could not suppress Aeolian vibrations, have been confirmed, due to the damping values being much less than critical damping (ζ ≪ 1). An additional conductor was tested, the ACSR Beresford conductor, whose self-damping factor was also not sufficient to suppress Aeolian vibration.