Study on Flow Field Simulation at Transmission Towers in Loess Hilly Regions Based on Circular Boundary Constraints

When using high-voltage transmission lines for energy transmission in loess hilly regions, local extreme wind fields such as turbulence and high-speed cyclones occur from time to time, which can cause many kinds of mechanical and electrical failures, seriously affecting the reliable and stable energy transmission of the power grid. The existing research focuses on the wind field simulation of ideal micro-terrain and actual terrain with mostly single micro-terrain characteristics. Model boundary constraints and the influence of constrained boundaries are the main problems that need to be solved to accurately model and simulate complex flow fields. In this paper, a flow field simulation method based on circular boundary constraints is carried out. During the study, the influence of the model boundary and the selection conditions of the modeling range are systematically analyzed. It is more suitable to make sure that the air domain is 4 times higher than the height of the hill undulations, in addition to ensuring that there should be a minimum of 400 m between the study region and the boundary. Then, an actual terrain model of a power grid line in Shanxi is established, through the method proposed in this paper, the wind speed at the location of the transmission tower line under different wind directions is analyzed, and it is found thatwhen the incidence direction is 45 degrees north by east the wind speed is the highest. The findings demonstrate that the circular boundary model has the advantage of more easily adjusting the wind incidence direction, in addition to theoretically reducing the errors caused by traditional models in boundary processing. It can accurately obtain the distribution characteristics of the flow field affected by the terrain, and quickly screen out the extreme working conditions that are most harmful to the transmission lines in the actual transmission line for energy transmission in complex loess hilly regions.