三维瞬态风场下覆冰导线舞动响应研究

Galloping of iced bundle conductors in 3D fluctuating wind field

为研究三维瞬态风场下输电线路舞动响应特性,以覆冰四分裂导线为例,根据三维随机流场生成方法和脉动风速功率谱,逐点模拟覆冰分裂导线周边的脉动风速场,并运用考虑子导线扭转效应的分裂导线舞动非线性有限元法对新月形和D形覆冰输电线路在均匀流场、一维脉动风速场和三维瞬态风场下进行舞动分析,比较了三类流场下导线舞动响应的异同之处,在此基础上讨论风场湍流成分对舞动的影响机制。研究结果表明:三维瞬态风场的脉动特性使得导线在一个振动周期内吸收的能量不再保持恒定,造成舞动响应始终伴随有一定程度的随机振动,舞动幅值无法最终达到稳定状态;同时,风场瞬态效应能提高覆冰导线舞动最大振幅,特别是D形覆冰下能使其提高一倍以上。三维瞬态风场的脉动特性在输电线路设计过程中应引起足够的关注。

Turbulence affects the galloping of overhead transmission lines.By virtue of the 3D random flow generation method and wind power spectral density function,1D and 3D fluctuating wind fields were simulated point by point around iced quad-bundle conductors.By applying the finite element method considering the torsional effect, galloping responses were obtained and compared under three types of wind flows.On this basis,the mechanism of the influence of wind turbulence on galloping was discussed.The results show that due to the turbulence of 3D random wind field,the varying energy absorbed in a single vibration cycle leads to the randomness of galloping response with unstable amplitude and the maximum amplitude could be enlarged,which could be more than twice for the D-shape ice accretion. The turbulence of 3D random wind field should be paid great attention to in the design of transmission lines.