任意高差的多档输电线动刚度理论建模

Theoretical modeling of dynamic stiffness for multi-span transmission line with arbitrary height difference

针对目前多档输电线动力特性研究中存在的不足,将任意一档导线视为子结构并基于现有的索振动理论获得了其动张力;利用相邻两档导线的动张力建立了悬垂绝缘子串绕其悬挂点摆动的动力学方程;综合每一档导线的振动方程以及悬垂绝缘子串的摆动方程建立了两档及三档输电线的动力学方程,求解得到由端部位移激励产生的动刚度;通过对动刚度进行分析得到了多档输电线的固有频率以及模态的理论表达形式;建立了小高差的两档及三档导线的有限元模型,理论分析结果与有限元结果一致,验证了理论公式的正确性。本文提出的动刚度理论对于研究多档输电线的动态响应具有重要的应用价值。

Aimed at deficiencies in the current researches of the dynamic characteristics of multi-span transmission line,the kinetic equations of a two-span and a three-span transmission lines,which consist of the vibration equation of each span and swing equation of insulator string,are established.Firstly,a span is regarded as a substructure and its dynamic tension is obtained based on the existing cable vibration theory.Using the dynamic tensions of two adjacent spans,the dynamic equation of the suspension insulator string around its suspension point is obtained.The dynamic stiffness generated by the end displacement excitation is determined.The natural frequency and the theoretical modal expression of the multi-span transmission lines are obtained by analyzing the dynamic stiffness.The finite element model of the two-span and three-span transmission lines with small height difference is established.The theoretical analysis results are consistent with the finite element results,and the correctness of the theoretical formula is verified.The dynamic stiffness theory proposed in this paper has important application value for studying the dynamic response of multi-span transmission line.