覆冰四分裂导线的气动特性与舞动特性

针对覆冰四分裂导线气动特性、舞动特性研究的缺乏,进行了覆冰四分裂导线风洞试验,并系统地研究了覆冰四分裂导线的舞动特性。首先进行了覆冰四分裂导线风洞试验,得到了覆冰四分裂导线的气动力系数,接着采用等效替代法得到了覆冰四分裂导线中心轴处的等效气动力系数,再结合Den-Hartog横向驰振机理分析了覆冰四分裂导线等效气动力系数的稳定区。基于Hamilton原理,推导了二自由度覆冰导线的舞动方程,并求得了气动力系数的三次拟合曲线一般表达式。根据风洞试验得到的气动力系数,系统地研究了覆冰四分裂导线的舞动特性。结果表明:由于尾流效应的存在,相同材料的子导线的气动力系数却存在明显的差异,因此考虑覆冰四分裂导线中某一根子导线的舞动特性并不能反映覆冰四分裂导线整体的舞动特性;覆冰四分裂导线开始振动时主要以z轴方向的位移为主,随后y轴方向的位移慢慢增加,振动稳定后y轴方向的位移远大于z轴方向的位移,点的运动轨迹近视为椭圆。研究结果有助于防舞、抑舞技术的开发。

Wind Tunnel Test and Galloping Characteristics of Iced Four-Bundle Conductor

Firstly, wind tunnel test of iced quad bundle conductor are carried out, and the aerodynamic coefficients of iced quad bundle conductor are obtained. Then the equivalent aerodynamic coefficients at the central axis of iced quad bundle conductor are obtained by equivalent substitution method. Then, the stable region of the equivalent aerodynamic coefficients of iced quad bundle conductor is analyzed by combining the Den-Hartog galloping mechanism . The cubic fitting expression about aerodynamic coefficients with 2-DOFs is derived, and the galloping characteristics of iced quad bundle conductor are studied by combining the aerodynamic coefficients obtained by wind tunnel test. The experimental results show that the aerodynamic coefficients of each sub-conductor with the same material are obviously different due to the existence of wake effects. Therefore, considering the galloping characteristics of a sub-conductor of quad bundle conductor cannot reflect the galloping characteristics of the whole quad bundle conductor. The results of galloping characteristics show that the displacement in the z-axis direction is dominant at the beginning of the vibration, and then the displacement in the y-axis direction increases slowly due to the negative slope of the aerodynamic loads on the conductor. The displacement in the y-axis direction is much larger than the displacement in the z-axis direction after the vibration is stabilized, and the trajectory of the point could be regarded as an ellipse.