Analysis, Prediction, and Mitigation of Vortex Induced Vibrations in Substation Structures

As modern utility structures move toward taller and more flexible designs, the problems of wind effects on these structures have become increasingly apparent. Vortex-induced vibration (VIV) is more complex than a mere resonant forcing problem. The complexity and uncertainty of the wind field and its interaction with structures that necessitate such an interdisciplinary approach, involving scientific fields such as meteorology, fluid dynamics, statistical theory of turbulence, structural dynamics, and probabilistic methods. Many structures used in substations can be prone to this problem. Based on some field reports of structural vibration, a study is performed to better understand the VIV issue and find ways to predict and mitigate/prevent it. This paper presents observed vibration cases, theory behind the phenomenon, and a numerical analysis to predict and investigate the VIV effects using modal analysis and ANSYS 3D two-way fluid structure interaction (FSI) models. The cases are updated and validated using field structural vibration and wind monitoring data. The paper concludes with some recommendations on how to identify critical structures, in addition to considerations that need to be taken into account during the design of these substations structures including fatigue design, and mitigation approaches to new or in-service structures.