输电线等效刚度计算方法及舞动分析

Calculation method for equivalent stiffness of transmission lines and analysis of galloping

针对考虑相邻档输电线影响的架空输电线路舞动问题,提出了一种计算相邻档及绝缘子串等效刚度的方法。通过分析外部载荷作用下输电线长度变化情况,推导出单档输电线等效刚度的理论公式,同时研究了张力和高差对等效刚度的影响;针对有绝缘子串的单档及两档输电线进行力学分析,获得输电线等效刚度理论公式,该公式考虑了输电线上悬垂绝缘子串,同时包含了档距和高差等参数,可将该公式扩展到任意连续档输电线等效刚度的计算中。与有限元计算结果对比表明,该理论公式对连续档输电线等效刚度计算具有较高的精度,水平等效刚度的最大误差为2.7%。同时建立了两端有弹簧约束的单档导线的舞动方程,考察了两端约束弹簧刚度对舞动幅值的影响。结果表明,随着等效弹簧刚度减小,竖向舞动幅值先增加后减少。本研究可为理论分析架空输电线路舞动提供有效支持。

For the galloping of overhead transmission lines, considering the interactions of neighbouring spans, a calculation method for the equivalent stiffness of neighbouring spans and insulator strings is presented. First, thetheoretical formula for the equivalent stiffness of single span transmission line is obtained, by analyzing the length change of transmission line under the loads, the effects of tension and height on the equivalent stiffness are also studied in particular. Then, the theoretical formula of the equivalent stiffness for single-span and two-span transmission line with insulator string are obtained, which contain insulator string, span, height and other parameters, and the formulas can be generalized to arbitrary continuous spans. Compared with the finite element results, the theoretical formula has higher precision for continuous span transmission lines. The maximum error of horizontal equivalent stiffness is within 2.7%. Finally, the galloping equation of the single span transmission line with spring constraints at both ends is established, and the effect of the spring stiffness on the galloping amplitude is investigated. The results show that the amplitude of vertical galloping increases first and then decreases as the equivalent spring stiffness decreases. Our studies provide important theoretical support for the theoretical analysis of overhead transmission line galloping.