The Optimal Layout Of Spacers And The Numerical Analysis Of Iced Conductor Galloping

Iced conductor galloping and subspan oscillation, which are both important subjects concerned with scholars of domestic and overseas, do serious harm to the safe operation of transmission lines. But for study on the problem of conductor galloping, based on traditional galloping mechanism, most scholars used discrete theory model or the finite element method, and simplified model, these methods cannot fully reflect characteristics of vibration of the continuum structure. Based on the studies of domestic and overseas, this paper, comprehensive considering the factors which affect conductor galloping and holding that iced conductor rotates around its center of mass, established continuum dynamics model and studied on complexity high-dimensional nonlinear galloping.First, nonlinear integer programming with constraint condition was solved, and Lingo software was used to program to solve the K-T points. Then, based on the maximization principle of the sum of the absolute value of differential value of adjacent span in the whole span and considering past certain principles and experience, layout optimization of spacers was achieved by using Fortran language programming. The specific calculation steps were listed. And then layout optimization of different spans was enumerated.Based on Den.Hartog vertical single degree of freedom principle and Hamilton principle, the dynamic model of vertical single degree of freedom was established in the wind-deviation plane, whose high order terms reached to third-order term, and then the influence of system and environmental parameters on torsion amplitude and critical wind speed was analyzed. Then anti-galloping measures were proposed according to the above results.Based on O.Nigol galloping mechanism and Hamilton principle, a vertical-torsion coupling galloping model for iced conductor rotating around its center of mass in the wind-deviation plane was built. The influence of parameters on galloping amplitude and critical wind velocity were analyzed. Under certain conditions, a new phenomenon was found that the vertical amplitude was zero but the torsion amplitude was not, so a single degree of freedom of torsion vibration model was established. And then the influence of system and environmental parameters on torsion amplitude and critical wind speed and compared the torsion amplitude of two models was analyzed.When iced conductor galloped, not only vertical and torsional direction vibration occurred, but also horizontal direction vibration, so the couple model of three degrees of freedom was built. The displacement-time curves of three directions were achieved, and the influence of parameters on galloping amplitude of vertical, torsion and horizontal and on critical wind velocity were analyzed. The basic galloping characteristics were obtained.Finally, in the same parameter conditions, the vertical and torsional vibration amplitude and the critical velocity were compared and analyzed. Couple model with three degrees of freedom best embodied characteristics of iced conductor galloping, and model with two degrees of freedom can also solve practical engineering problems, while model with one degree of freedom can only qualitatively reflect some trends of characteristics of galloping.