Finite Element Analysis Of Transmission Line Galloping

The galloping threatens the safe of the transmission lines, and it can lead to severe disruptions in the electrical power supply, and resulting in major economic loss. However, The galloping characteristics are complex, so it's difficult to prevent and cure the galloping in practice. In order to guarantee the safety and reliability of electrical network,the galloping phenomenon of power transmission lines must be in-depth study. In this paper, a single degree of freedom, two degrees of freedom model, three degrees of freedom, incremental harmonic balance method in galloping on the application of several aspects of ice dancing power lines has been studied . The main contents are:A single degree of freedom and two degrees of freedom mechanical model is established,and the transmission line dancing rules is analyzed. Simplified force model is used, established by the D'Alembert principle of infinitesimal movement, and equilibrium equation derived single degree of freedom and two degrees of freedom dynamic equations, and verify the accuracy of self mathematics program. Analysis showed that the vertical movement is the main in galloping. To the smaller torsional stiffness, the results are relatively large vertical direction. When torsional stiffness is relatively large, results is relatively accurate.The three-degree-of-freedom model for galloping is derived three nodes . Forst of all, the space of the transmission line cable is discreted with three node element, and according to Hamilton principle and the variational principle, the general method for establishing galloping finite element model is provided. Finite element model of transmission line dancing specific expression forma is given. Finally pointed out that traditional cable element stiffness matrix than this article derivation stiffness matrix too big, cause tension on the transmission tower small calculated values. Finally by crafting a Matlab program, using the time integral algorithm on nonlinear equations to prove the accuracy of this model.Using incremental harmonic balance method (IHB) of transmission line dancing issues, and then use incremental harmonic balance method for calculating the mathematical model. Firstly, harmonic load is used to analyse the characteristics of the cable, then to analyse the problems of galloping. The calculation results show that the ultimate unbalanced force tends to zero, shows that the method used in the field is rational. The analysis was that first-order harmonic is significantly smaller, the two-order harmonic analysis can meet the accuracy requirements.Incremental harmonic balance method (IHB) can effectively solve the nonlinear problem of galloping to analyze nonlinear phenomena such as limit cycle, and compared with the numerical results with high accuracy. The frequency interval that can be locked, you can analysis parameters change on vibration characteristics.