基于3自由度的新月形覆冰输电线舞动稳定性研究

Research on Stability of Transmission Lines with Crescent Shaped Ice Based on Three Degrees of Freedom

针对覆冰输电线舞动问题提出了一种基于非对称空气动力系数矩阵的临界风速计算方法.基于拟静态理论得到覆冰输电线的气动载荷,该气动载荷考虑了横向运动以及扭转运动对相对风攻角的影响,最后建立等效的3自由度覆冰输电线舞动模型.在初始风攻角处对气动载荷进行泰勒展开,得到非对称的线性空气动力系数矩阵.结合3自由度振动方程以及非对称空气动力系数矩阵,采用Rourh-Hurwitz准则计算覆冰输电线舞动发生的临界风速.通过风洞实验测得新月型覆冰单导线的空气动力系数,根据本文提出的理论分析了竖向振动频率、面外振动频率以及扭转振动频率对临界风速的影响,最后与DenHartog理论得到的临界风速进行了对比.本文研究成果对于指导覆冰输电线路防舞设计具有理论意义.

Focusing on the galloping of iced transmission lines, a method based on the asymmetric aerodynamic coefficient matrix is presented to calculate the critical wind speed. Based on the quasi-static method, the aerodynamic load of the iced transmission lines, which takes into account the effects of the transverse and torsional motions on the relative attack angle, is obtained. A 3-DOF model for iced transmission lines is established. The asymmetric aerodynamic coefficient matrix is presented by the Taylor series expansion of the aerodynamic load at the initial attack angle. Combined with the 3-DOF model and the asymmetrical aerodynamic coefficient matrix, using the Rourh-Hurwitz criterion, the critical wind speed is calculated to assess the galloping of iced transmission lines. The aerodynamic coefficients of the conductor with crescent shaped ice are measured from the wind tunnel test. The effects of vertical vibration frequency, transverse vibration frequency and torsional vibration frequency on the critical wind speed are investigated using the theory presented in this paper. The critical wind speeds obtained from this paper are compared with those obtained by DenHartog theory. The research results of this paper have theoretical significance for guiding the anti-galloping design of iced transmission lines.