SELF-EXCITED WIND-INDUCED VIBRATIONS AND LIMIT-CYCLES IN BUNDLED CONDUCTORS

Wake-induced oscillations on bundled conductors of overhead transmissi on lines are investigated. These oscillations are due to the leeward c onductor lying in the wake of the windward one. We consider a twin hor izontal bundle of overhead lines. First of all, the critical wind velo city (bifurcation point) of incipient flutter is identified [3, 4]. A nonlinear analysis is adopted to investigate the post-bifurcational be haviour of the oscillations. Using, if necessary a reduction to the ce nter manifold, and an additional normal form transformation we obtain amplitude equations which can be analyzed qualitatively with regard to the unfolding parameters.