Wind Tunnel Test And Numerical Simulation On Galloping Of Iced Conductor

Gal oping is a low frequency, high amplitude self-excited under mid/low wind velocity, which causes serious damage to the structure and endanger the safe operation of the power grid. There are several forms of icing cross-section under different climatic conditions, in which crescent shaped cross-section is a typical form. In this paper, the study mainly considers on crescent shaped cross-section, and the aerodynamic characteristic of the conductor were studied by numerical simulation(CFD) and wind tunnel test.The main contents of the paper are as follows:First of al, this paper has studied the aerodynamic characteristic of the crescentshaped iced conductor under different wind attack angle by numerical simulation, and analysis the stability characteristic of conductor with Den Hartog vertical mechanism of gal oping and Nigol torsional induced mechanism of gal oping. The results have shown that iced conductor may generate negative aerodynamic damping in the vertical and torsional directions under some wind attack angle. At the same time, this paper has analysis the flow fluid information of iced conductor under different wind attack angel using PIV technology. The results have shown that both the flow separation position and wake vortex integral scale will change with different wind attack angle.Then, this paper has completed the wind tunnel test of crescent iced conductor aeroelastic models, and analysis vibration characteristic and spectral characteristics of the iced conductor under different wind speed and attack angle. The results show that the gal oping of iced conductor can be divided into vertical gal oping and vertical-torsion coupling gal oping. Vertical gal oping is a vertical self-excited vibration due to the negative aerodynamic damping in vertical, and general y only occur in a few specific wind speed and attack angle. Vertical-torsional coupling gal oping is generated by the negative aerodynamic damping in torsional, and keep inputting energy to vertical and cause substantial vibration in vertical. When the gal oping happened, the vibration frequency of the three direction become the same value.Finally, this paper has studied the variation of the negative aerodynamic damping with wind speed by numerical simulation. The results show that crescent iced conductor can’t generate negative aerodynamic damping in transverse. When the negative aerodynamic damping is bigger than the inherent damping, the iced conductor will gal op in the corresponding direction. When the iced conductor vibration diverges in and torsional, the wind attack angle will change, which cause the vertical aerodynamic damping and torsional aerodynamic damping to change. When the negative torsional aerodynamic damping and inherent damping offset, and the torsional vibration response gradually remains stable.