摘要
输电线路覆冰后的脱冰动力分析十分复杂。以某1000 kV大跨越为工程背景,借助非线性有限元方法建立塔-线耦合模型。为了考虑线路覆冰的弯曲刚度,采用梁单元模拟覆冰,采用单元生死法模拟脱冰,分析塔-线体系对线路脱冰的动力响应。结果表明,线路覆冰后体系的低阶振型基本没有变化,而自振周期变长了;地线脱冰后体系的振动响应衰减较快,而导线脱冰后体系的振动响应衰减较慢。同时,输电塔的位移响应,脱冰50%比脱冰100%时小,而对跨中电线的跳跃幅值,脱冰50%比脱冰100%时大。
Dynamic analysis of transmission lines subjected to ice-shedding loads is very complex. Here, a 1000kV long-span electric transmission tower-line system is taken as the study object, and the tower-line coupling model built with nonlinear finite element method is proposed to calculate the dynamic response of the system subjected to ice shedding. In order to consider the equivalent bending stiffness of ice, a 3-D two-node beam element in parallel to each cable element is used to model accreted ice. In order to simulate the process of ice detachment from wires, the method of 'element death' is used to model ice shedding. The result shows that the lower modal shapes of the tower-line system have no change after wires are accreted by ice, but the vibration period enlarged. It is also seen that the system vibration decays more quickly after ice on ground wires is shedded, compared to the vibration induced by ice shedding from conducting wires. In addition, compared two cases of ice-shedding 50% and ice-shedding 100%, the longitudinal displacement responses of the tower in the former case are smaller than those in the latter case; but on the contrary, the vertical displacements of the line at mid span in the former case are bigger than those in the latter case.
出处
《振动与冲击》
EI
CSCD
北大核心
2008年第9期32-34,50,共4页
Journal of Vibration and Shock
基金
国家电网公司科技项目(SGKJ[2007]413)
关键词
塔-线耦合
线路覆冰
线路脱冰
振动
有限元
tower-line coupling
ice accretion
ice shedding
vibration
finite element method
