Simulation Research on Suppression Measures Against Severe Ice-Shedding of Ultra-high Voltage Alternating Current Ultra-Long Span Transmission Lines

In the section across valleys and rivers, it is often necessary to set up ultra-high voltage alternating current (UHVAC) ultra-long span transmission line. UHVAC ultra-long span is more prone to phase-to-phase flashover, conductor breaking and damage on insulation due to the larger span, larger diameter of conductor and more splits when ice-shedding occurs. Based on the three-degree-of-freedom (3DOF) transmission line dynamic model independently developed by Tsinghua University, the relationship between the severity of ice-shedding and different ice-shedding conditions were analyzed and the influence of short span sections on both sides was also discussed. In this paper, three kinds of spacer installation methods were applied to the model under severe ice-shedding conditions. According to the calculation, it was found that suppression effects were different and the transmission model can meet the safety requirements.