Multimodal analysis of saddle micro-terrain prone to wind disasters on overhead transmission lines

Abstract

Pervasive micro-terrain is a significant contributor to wind disasters on transmission lines. This study explores the effect of saddle micro-terrain on the wind field of transmission lines and proposes relevant models and analysis methods. Firstly, the characteristic elements and parameters of saddle micro-terrain are extracted using DEM and established representative cross-sections for classification. Subsequently, a multimodal computational model is developed, considering the geographical and meteorological features and the sag model of transmission lines under micro-terrain. This study calculates wind field distribution and conductor wind loads for three types of saddle micro-terrain conditions, revealing an exponential growth trend of wind loads with increasing wind speeds. The results indicate that in transmission lines at saddle areas, the sag region does not intrude into the boundary layer, with a wind speed growth rate of only 0.18, resulting in relatively stable wind loads. In contrast, for transmission lines at saddle areas in secondary mountain ranges and dual-mountain saddle regions, wind speed growth rates reach 0.97 and 1.53, respectively, indicating higher disaster risks. This research provides a basis for distinguishing and disaster prevention in mountainous transmission lines' micro-terrain variations, offering significant contributions to enhancing wind-resistant design standards in mountainous regions.