覆冰荷载下的架空输电线气动稳定性分析

Aerodynamic stability analysis of ice-covered overhead transmission lines

偏心覆冰导线在风激励下极易诱发舞动,研究架空输电线在覆冰荷载下的气动稳定性具有重要意义.传统Den Hartog判别准则求出的是一种近似解,仅适用于攻角较小的情况。在该基础上,更为精确地推导了舞动临界风速与相应来流攻角的关系.算例结果表明,对于重覆冰地区的架空输电导线,在风荷载作用下,极易引起导线的动力失稳,进而引起整个塔线体系的动力失稳甚至倒塌.该气动稳定性分析结果将为线路设计提供技术支持.

Asymmetric icing conductors are prone to gallop under the action of wind. Study on the aerodynamic stability analysis of ice-covered overhead transmission lines is of great significance. The traditional Den Hartog criterion is an approximate solution, and only applicable to the situa- tion of small attack angle. Based on the traditional Den Hartog criterion, the more accurate relationship between the critical wind velocity of the galloping phenomenon and the attack angle is deduced in this paper. The numerical analysis of examples shows that, as to the heavily ice-cov- ered overhead transmission lines, the wind load may easily lead to the dynamic buckling of the conductors and consequently result in the dynamic buckling of the whole tower-and-line system. In the process of transmission lines design, it is necessary to take the galloping phenomenon into account.