Investigation On Anti-galloping Techniques Of Iced Quad Bundle Conductors Galloping

Galloping can cause different kinds of damage, all of these can brings a great challenge to the national economy and security. Thus, the investigation on anti-galloping has a very important significance in engineering and practice. This paper based on domestic and international research and focus on the mechanism and effect of anti-galloping iced quad bundle conductors and the main work includes the following several parts:(1) Based on galloping characteristics of iced quad-bundled conductors and domestic and international research of anti-galloping device is designed. The iced quad bundle conductors are simplified as a single conductor. Then a nonlinear dynamical equation for anti-galloping devices and iced quad-bundled conductors of two degrees of freedom in vertical and torsional directions is established by means of the Hamilton principle, and the final dynamic equations are derived.(2) The numerical analysis for dynamic equations of system is achieved and the displacement and time curves and amplitude-frequency curves are also obtained and so on. Simultaneously, the parameter optimization of the anti-galloping device is numerically carried out. The numerical results show that the effect of the new anti-galloping device is evident when the natural frequency of the spring mass system consistent with the conductor wave frequency and at the same time torsional displacement can be reduced under low wind speed. So the anti-galloping device is prospective in engineering applications.(3) Using dimensionless method to analysis the nonlinear dynamical equation for anti-galloping devices and iced quad-bundled conductors and found the conductor torsional vibration response is strongly nonlinear. In order to avoid the complexity of strongly nonlinear analysis, the conductor torsional vibration response is fitted to a cubic polynomial function of wind velocity?elastic stiffness?mass ratio and damping ratio of anti-galloping device. To be more accurate, piecewise function is used to fit the curve. Then by using the average method, the vibration of system is analyzed corresponding to the non-internal resonance. The results show that the approximate analytical solution of system is basically consistent with the numerical solution.(4) The bifurcation equations with different bifurcation parameters such as wind velocity?mass ratio and damping ratio of anti-galloping device is analyzed by using the singularity theory.And the corresponding transition sets and bifurcation diagrams of system are obtained. Then switching the unfolding parameter plan of system to the physical parameter plan, the planar graphs of physical parameter are obtained. It can got the best value region of the anti-galloping device and can be applied for the design of the anti-galloping device.(5) The beam vibration theory is adopted to research on damping property of damper. The resonance dwell method under sinusoidal excitation is applied to the damper vibration experiment. The contribution of different modes in damping energy is analyzed. The effect of different damping for vibration damping performance is considered. Damping coefficient formula is deduced. By the principle of energy balance theory, the damping property curve is calculated. Results show that steel strand deformation directly affects the damping value and verify the damping property of dampers. At the same time, the mass change of hammer damper can affect the damping property curve. These conclusions can be applied for the anti-vibration design of dampers.