Galloping Mechanism and Anti-Galloping Design of UHV Transmission Lines in Extreme Meteorological Environments

Intensifying extreme weather conditions have significantly increased transmission conductor galloping. To address this, this study proposes an anti-galloping composite inter-phase spacer arrangement for 1,000 kV AC UHV lines with a three-phase vertical configuration. Using a 4DOF nonlinear simulation model and the finite element method, multi-span conductor-insulator systems were analyzed to evaluate variations in minimum inter-phase distance. Results reveal that galloping severity and spacer efficacy correlate strongly with tension section span lengths, leading to five optimized arrangement schemes. Specifically, for spans below 300 m, installing 2 spacers (at 1/3 upper-middle and 2/3 middle-lower positions) achieves 96% suppression efficiency. For 300–360 m spans, 3 spacers (1/4, 3/4 upper-middle; 1/2 middle-lower) yield 90% efficiency. Spans of 360–500 m require 4 spacers (1/3, 2/3 upper-middle; 1/4, 3/4 middle-lower) for 95% efficiency. For 500–800 m spans, 6 spacers (1/5, 1/2, 4/5 upper-middle; 1/7, 1/2, 6/7 middle-lower) achieve 94% efficiency, while 800–1000 m spans need 7 spacers (1/4, 1/2, 3/4 upper-middle; 1/7, 2/5, 3/5, 7/8 middle-lower) for 87% efficiency. Spans exceeding 1000 m require custom verification based on local factors. Numerical results confirm that postdeployment, previously pronounced periodic dynamic oscillations were effectively suppressed, resulting in stabilized inter-phase distances. By successfully reducing galloping amplitude and spacer tensile force, the proposed schemes have passed rigorous safety verifications, demonstrating exceptional engineering viability for practical applications.