输电线强风抖振顺风向动张力的理论与试验

Theories and Experiments for Along-Wind Dynamic Tension of Buffeting in Strong Wind of Overhead Transmission Line

架空输电线路具有跨度大且较柔和质量轻且阻尼小的特点,对风荷载的作用十分敏感。脉动风作用下导线连接处及其端部的抖振动张力,是输电线路结构设计研究的重难点。本文基于结构随机振动理论和索结构力学,将静力平衡状态下的动力响应分为背景响应和共振响应,重点讨论通过影响线函数确定的背景分量,给出了顺风向(垂直于导线平面方向)动张力的背景响应功率谱函数及均方根的频域解析解。通过设计且完成了双跨四分裂输电线标准气动弹性模型风洞试验,并考虑耐张绝缘子、I形绝缘子和V形绝缘子的3种连接方式,采用高频测力天平装置,考察了风振空间动张力的作用规律。研究表明,跨中连接处绝缘子类型对顺风向张力的影响较为明显。不可忽略的气动阻尼效应使得背景响应占动力总响应的绝大部分。同时通过风洞试验也验证了本文理论模型具有相对的精确性。

The overhead transmission line has the characteristics of large span,soft quality and low damping,it is very sensitive to the action of wind load.The buffeting tensions at the junction of the conductor and its end under the action of the fluctuating wind are the most difficult points in the structural design of the transmission line.Based on the theory of random vibration of structure and the mechanics of cable structure,the dynamic response in static equilibrium state is divided into background response and resonant response.The background component determined by using the effect string function is discussed emphatically.The frequency domain analytical solution of the background response power spectrum function and the root mean square of the along-wind dynamic tension(perpendicular to the plane direction of the conductor)are given.The wind tunnel test of full aeroelastic model of two-span 4-bundle conductor is designed and completed.Considering the three connection modes of tensile insulator,I insulator and V insulator.The action law of dynamic tension in wind-induced space is investigated by using high frequency force balance device.The study shows that the influence of different types of insulators on the along-wind tension response is obvious.The nonnegligible aerodynamic damping effect makes the background response account for most of the total dynamic response.At the same time,the relative accuracy of the theoretical model is verified by wind tunnel test.