移动通信铁塔直击雷电流分布的研究

为研究雷击移动通信基站铁塔的电流分布特性,提出了一种全新的电路方法,创建了一个描述铁塔及其接地网构成的网络系统的电路模型。分析了铁塔上的雷电流分布及铁塔的冲击阻抗特性。仿真表明:铁塔及天线电缆屏蔽层上的雷电流分布情况与铁塔结构及雷击位置有关,但几乎不受大地电阻率的影响;而且,任意位置的直击雷在接地网对称位置的接地体上产生几乎相同的入地电流;"铁塔—接地网"网络的整体电阻和电抗随雷击点距地面高度的增加会有略微增大,其中电抗的变化比电阻的略大。研究成果为雷电防护设计提供了重要参考。

Study on Improvement of Seismic Performance of Transmission Tower Using Viscous Damper

The earthquake resistance of transmission tower has been often discussed from the viewpoint of reinforcing the foundation of steel tower, but there are also few studies considering the damping characteristics of the tower. This paper focuses on the viscous damper which has been adopted for seismic reinforcement of bridges in recent years. The purpose of this study is to improve the seismic performance of steel tower by giving the high damping to the tower. We construct a single tower model considering the influence of transmission line, and then simulate the vibration characteristics and seismic behavior of the tower by the eigenvalue analysis and the dynamic response analysis. The results show that the transmission tower with viscous damper can reduce its own response effectively and drastically. This research concludes that it is necessary to consider the extreme increase of steel tower＇s response depending on the seismic wave and the collapse of steel tower can be avoided by using the optimum damper in the design of the transmission tower.

中波天调网络的防雷措施

中波大功率铁塔天线、馈线都建在野外,由于天电感应、雷击、风、雨、雪、鸟、昆虫等动物的外界影响,会引起天线和馈线打火、放电。不管哪种原因引起的天线和馈线短路、开路或阻抗变化,都会在馈线上产生驻波,导致发射机不能正常工作,甚至损坏元器件。因此必须做好中波天调网络的防雷处理。本文对常见的几种防雷措施和放电球的间隙如何确定加以论述。