ON THE ENERGY-DISSIPATION IN SPACER DAMPERS IN BUNDLED CONDUCTORS OF OVERHEAD TRANSMISSION-LINES

In high voltage overhead transmission lines, bundles of conductors are used frequently for mechanical and electrical reasons. These bundled conductors are particularly susceptible to wind excited vibrations in the frequency range approximately from 10 to 60 Hz, due to vortex shedding. The usual dampers of the Stockbridge or of a similar type located near the suspension clamp do not lead to pervasive damping of the whole bundle. In recent years self-damping spacers have therefore been used to limit the danger of conductor fatigue due to aeolian vibrations. The numerical treatment of the boundary value problem for bundles equipped with self-damping spacers leads to complicated and poorly conditioned equations. In the present paper, a self-damping spacer is considered in a bundle of four conductors. The energy dissipation associated with the mathematical model-for this spacer can be expressed in the form of a symmetric matrix of dimension 16 x 16. By solving the relatively small eigenvalue problem defined by the corresponding 16 x 16 matrix, the spacer damper can be optimized with respect to mechanical energy dissipation by maximizing the smallest real part of its eigenvalues.