雷击电力调度大楼微波塔时天馈线过电压计算

针对雷击电力调度大楼微波塔时天馈线冲击感应过电压可能危及微波接收设备的问题,仿真计算研究了天馈线屏蔽层的雷电分流系数、天馈线感应过电压水平及影响因素。结果表明:天馈线感应过电压随大楼接地电阻减小而降低,随天馈线长度增长而稍有降低,与雷击注入的雷电流大小成正比而分流系数不变;天馈线设备端装备的保护器应尽量靠近被保护设备安装,其动作延时越短越好。

Calculation of Induced Voltage of Communication Line Attached to Microwave Tower of Electric Power Building Caused by Lightning

When lightning strike to microwave tower of electric power building, part of lightning current will flow through shield layer of microwave communication line, and will produce lightning induced voltage in the line between core line and its shield layer. The voltage can endanger microwave receiving equipment when it is high enough. Calculation on lightning current distribution and induced voltage of microwave communication line is conducted in this paper. The results show that ground resistance affects induced voltage level of communication line largely. The less is the ground resistance, the less is the amplitude of induced voltage. The amplitude of induced voltage will decrease with the increase of communication line length slightly, and increase with the amplitude of lightning current linearly. Microwave equipment lightning protector should be fixed as close as possible to the equipment, and the delay time of discharge should also be shorten as possible.