Stability of a stranded, sagged, lightly iced electrical power transmission cable subjected to aerodynamic forces and moment is studied. Small oscillations in three Cartesian directions about wind loaded equilibrium position and torsional oscillations are considered. A finite element analysis of the linearized coupled differential equations is performed. Stability is determined by the sign — stable if negative — of the real parts of the eigenvalues of the linear system. It is shown that a lightly iced cable without inertial coupling that is Den Hartog stable and subjected to an aerodynamic moment having a positive slope can still be unstable due to the combined effect of stranded nature of cable construction, wind, and aerodynamic coefficients. It appears that this effect is less significant if the fundamental torsional frequency is well separated from the first few vertical mode frequencies.

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