Abstract：Based on Hamilton’s principle, this paper formulates the nonlinear galloping equations of iced conductors, which couple three translational and one torsional degrees of freedom and involve the influence of eccentric icing. A new nonlinear finite element model of iced conductors in which the adjacent conductor spans and insulator strings are represented by linear springs is established here. Taking into account the nonlinear aerodynamic forces and the geometric nonlinearity caused by large amplitude galloping, the authors adopt the Newmark-β time integration algorithm in conjunction with modified Newton-Raphson nonlinear iteration strategy to solve those equations in finite element formulation. The numerical solutions of both amplitude and frequency obtained from the present method agree well with the measured values of the galloping of a D-shaped iced conductor, which proves that the current finite element model is accurate. The present research also indicates that the galloping is a kind of low-frequency vibration which mainly moves vertically and generally occurs around the first-order vertical natural frequency. The amplitudes and frequencies of the galloping are uniquely determined by the physical parameters of the transmission line and wind loads which are irrelevant to the initial state of the movements of the iced conductors.
2016, Vol. 37 
