Galloping Characteristics Of Iced Conductor In Full Angle Of Attack Range And Anti-Galloping Research Based On Vibration Damping Technology

Iced conductor galloping is a typical structural aerodynamic instability phenomenon,which can cause damage to the transmission tower and line system,such as metal fittings,rod damage and even tower collapses in serious cases.To solve the problem of frequent galloping in China and the lack of consummate theory and specific optimization design method for traditional anti-galloping measures,Galerkin method was proposed for galloping calculation considering both calculation accuracy and calculation efficiency.After a comprehensive study of the galloping characteristics of iced conductors,based on vibration damping technology,two kinds of anti-galloping damping methods were proposed.They were the tuned mass damper that provides damping force by relative motion of the free mass and the viscoelastic interphase spacer that provides damping force by relative motion between adjacent structures.In addition,the design and parameter optimization of a new type of anti-galloping tuned mass damper was studied.The main research contents are as follows1.Galloping shape and amplitude of multi-bundled conductor in full angle of attack range:The partial differential equation was established by an equivalent single conductor.The partial differential equation was discretized by Galerkin method and solved by non-linear Newmark-Beta method.By studying the relationship between the order of Galerkin function and the error of galloping amplitude calculation,the appropriate order of Galerkin function was selected to balance the calculation efficiency and accuracy.On this basis,the D-type iced conductor galloping was studied.The galloping amplitude of iced 8-bundled conductor in full angle of attack range was analyzed.The galloping time history,frequency characteristics and galloping shape were analyzed at the attack angle with the largest galloping amplitude.The galloping characteristics of D-type iced 8-bundled conductor were comprehensively studied to guide the prevention and control of galloping;2.Comparative study on anti-galloping effect of three types of TMDs on iced multi-bundled conductor:Based on the three-degree-of-freedom motion equation of multi-bundled conductor,the motion equations of the three-degree-of-freedom(3-DOF)conductor model and tuned mass dampers with vertical,torsional and vertical-torsional DOFs coupled were established.Lyapunov's first stability theorem was used to solve the galloping wind speed of conductor-damper system under different parameters.The frequency ratio and damping ratio of dampers were optimized.The galloping wind speed calculated was verified by numerical calculation.Finally,the full attack angle of galloping wind speed under the optimal damping parameters of different tuned mass dampers were compared,and the anti-galloping effect of three types of mass damper was analyzed and compared,and their applicability was studied;3.Design and parameter analysis of torsional eddy current tuned mass damper for anti-galloping:A new type of torsional eddy current tuned mass damper for anti-galloping was invented to prevent galloping of multi-bundled conductors.The design theory of the new type torsional eddy current mass damper was established.The motion equation of the transmission line and the torsional tuned mass damper system was derived.The galloping wind speed of the transmission line and the torsional tuned mass damper system was calculated by applying Lyapunov stability theorem.The non-linear Newmark-Beta method was used to calculate the galloping amplitude of the iced conductor and damper system.With regard to the galloping wind speed with the attack angle towards iced side and galloping amplitude with the attack angle towards non-iced side,the corresponding effects of damper parameters were studied in detail.The mechanism of the torsional mass damper in the galloping suppression of the multi-bundled iced conductor was discussed from the perspective of modal damping;4.Multi-objective satisfactory optimization of anti-galloping torsional tuned mass damper parameters based on genetic algorithm:Based on the concept of "satisfaction" in fuzzy mathematics and genetic algorithm,a multi-objective optimization method for the prevention and control of galloping of iced multi-bundled conductors was presented.The minimum galloping wind speed with the attack angle towards non-iced side was calculated by Lyapunov stability theorem,and the maximum vertical galloping amplitude was calculated by non-linear Newmark-Beta method under different wind speeds with the attack angle towards iced side.Applying a new sampling method for determining the weight coefficients of satisfaction,the optimal damping parameters of multiple torsional tuned mass dampers were obtained by multi-objective optimization based on genetic algorithm and compared with the multi-objective optimization results based on Pareto optimal theory.A more mature multi-objective optimization design method for iced multi-bundled conductor with anti-galloping mass dampers was established and studied;5.Theoretical research on anti-galloping viscoelastic damping interphase spacer:The partial differential equation of two-phase conductors and viscoelastic damping interphase spacer system was deduced.The first-order vertical mode of the conductors was considered.The ordinary differential equation of the two-phase conductor and viscoelastic interphase spacer system is obtained by applying the model assuming method.The formulas to calculate the amplitude of single-phase conductor and two-phase conductor viscoelastic interphase spacer system were derived by multiple scale method.The results of the galloping amplitude formulas were verified by numerical results.The effects of mass ratio,damping ratio,frequency ratio and equivalent stiffness ratio on the vertical galloping amplitude of iced conductors under different wind speeds were studied in the dimensionless parameter space.The effects of height difference,tension difference and weight difference of conductors on the vertical galloping amplitude were studied in physical parameter space.The anti-galloping mechanism of viscoelastic damping interphase spacer was an attempt to clarify.Finally,the finite element model of the three-phase conductors and viscoelastic damping interphase spacer system was established to verify the effectiveness of the anti-galloping damping interphase spacer in the actual three-phase conductors system.