Prediction Of Galloping Of Transmission Line Conductors By A Computational Aeroelastic Approach

Prediction of Galloping of Transmission Line Conductors by a Computational Aeroelastic Approach

"Various types of overhead transmission line vibration instabilities are introduced and their impact on reliability and serviceability of electrical power networks is discussed in detail. By following a historical background, different mechanisms to describe these events, particularly galloping, are investigated and the advantages and drawbacks of each method are discussed. In addition, important factors affecting the galloping and the necessary conditions to expect large instabilities are addressed. In order to overcome the limitations of the current methods, a practical cost-effective computational methodology, with adequate accuracy, is designed to study galloping as an aeroelastic instability problem in two- and three-dimensions for single and bundled conductors subjected to various wind and atmospheric icing conditions. The proposed methodology is a two-way loosely coupled fluid-structure interaction analysis consisting of three key modules: Computational Fluid Dynamics (CFD), Computational Structural Dynamics (CSD), and communication and data-handling modules. The CFD analysis module is based on the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations and uses the one-equation Spalart-Allmaras turbulence model for the Reynolds stresses. The conductor displacements obtained from the CSD analysis module are handled by the CFD module, using an Arbitrary Lagrangian Eulerian (ALE) formulation. In essence, the CSD module determines the nonlinear dynamic response of the conductors to the unsteady flow loading predicted by CFD analysis at each time increment. The nonlinear equations of the conductor's motion are solved by a direct time-step integration using the second order time-accurate and unconditionally stable Newmark-Beta operator (trapezoidal rule). Finally, due to the non-matching finite element grids used for fluid and structure discretization, a fast communication module is designed for load and displacement transfer between the CFD and CSD modules. The methodology is validated using the results of different two- and three-dimensional test cases reported in the open scientific literature, and detailed computational predictions of galloping events are presented for different incident wind conditions and ice accretions." --

Insights and Innovations in Structural Engineering, Mechanics and Computation

Insights and Innovations in Structural Engineering, Mechanics and Computation comprises 360 papers that were presented at the Sixth International Conference on Structural Engineering, Mechanics and Computation (SEMC 2016, Cape Town, South Africa, 5-7 September 2016). The papers reflect the broad scope of the SEMC conferences, and cover a wide range of engineering structures (buildings, bridges, towers, roofs, foundations, offshore structures, tunnels, dams, vessels, vehicles and machinery) and engineering materials (steel, aluminium, concrete, masonry, timber, glass, polymers, composites, laminates, smart materials).

Applied Mechanics Reviews