| Along with the development of Extra-high Voltage (EHV) and Ultra-high Voltage (UHV) transmission lines as well as the increase of the long-span transmission lines, the harms of icing-caused galloping and ice-shedding jumping in overhead transmission lines were extensively concerned. It is necessary to make a deep investigation and study in accordance with experience in the operation of EHV electric network.Analysis of site investigations and accidents were carried out in view of the galloping and ice-shedding of 500kV overhead transmission lines from Ertan to Zigong in the Liangshan area. The characteristics and laws of occuring accidents due to the galloping and ice-shedding of overhead transmission lines were summarized in high altitude area with serious ice covering.Furthermore, the effect of aerodynamics and the vibration characteristics as well as the stabilization calculation on bundled conductor line with galloping and ice-shedding were researched,Finally ,the analytical studies performed at Ontario Hydro can be used to conduct a parametric study of the Er-Zi lines. Furthermore, the related measures to improve the torsional stability for overhead transmission lines were proposed by the analysising of several accidents in this paper. After the increase in number of spacers, the torsional stability is increased. The resistance of the bundle to overturning can be increased by means other than spacer dampers, namely increasing the subconductor tension difference, lowering the center of mass of the bundle( by adding weights), and the installation of horizontal interphase spacers. |
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