多跨输电线路脱冰动力响应研究

DYNAMIC RESPONSE ANALYSIS OF MULTI-SPAN TRANSMISSION LINE TO ICE-SHEDDING SHOCK

提出了输电线路脱冰动力响应有限元分析方法,采用3自由度等参抛物线索单元模拟导线及覆冰,空间杆单元模拟绝缘子串,建立了多跨覆冰输电线路有限元模型。使用生死单元技术杀死覆冰单元来模拟脱冰瞬间,使动力分析时间范围包含由覆冰至脱冰的荷载突变过程,采用考虑几何非线性的隐式时间积分算法,利用自适应时间步技术克服收敛困难,对线路脱冰非线性动力方程进行时域求解。模拟了中跨和三跨脱冰两种情况,对脱冰跨数、线路张拉力、档距和绝缘子长度等参数对线路脱冰响应的影响进行了研究。

A finite element method is presented to analyze the dynamic responses of multi-span transmission lines to ice-shedding from conductors.While the isoparametric cable elements with parabolic shape functions are used to model the conductors of multi-span transmission lines and ice,spatial spar elements are used for the insulators.The impact load effects due to ice-shedding process are considered in the dynamic analysis by employing an element birth and death method.The implicit time integration algorithm considering geometric nonlinearity is utilized to solve the nonlinear dynamic equilibrium equations.The convergence difficulty of the implicit algorithm is overcome by using adaptive time steps.Two ice-shedding cases from one span and three spans are simulated to investigate the influences of a number of factors to the ice-shedding shock,such as ice-shedding spans,the tension of a conductor,the distance of a span and the length of a insulator string.