雷电电流的频谱和能量分析

摘要:

为了研究风电场中强大电磁干扰源雷电流的基本特性,利用脉冲函数作为2.6/50μs雷电流的解析表达式,将其与双指数函数表示的雷电电流进行比较说明其可用性。之后采用傅里叶变换和仿真计算的方法对雷电流的幅频特性以及所含能量进行了研究,得到相应的频谱图和能量分布图。经过分析得到的结论是:雷电流的频率在低频范围之内,能量主要集中在1～10 kHz之间,且雷电流脉冲上升越陡频率分量的初始振幅值越小,但是其包含的高频分量却越多。

Abstract:

The characteristics of the powerful EMI source － lighting current are mainly studied． Firstly，the pulse function is used as the analytical expression of the 2． 6 /50 μs lightning current，and then this expression is compared with the lighting current expressed by double － exponential function for explaining its usability． Secondly，the Fourier transform and simulation are adopted to research the amplitude － frequency characteristic and the energy content of lightning current，and the relevant spectrum diagram and the energy distribution are obtained． Finally，through the analysis，the conclusion is gotten that the frequency of lighting current belongs to the low frequency rang and its energy mainly concentrates between 1 ～ 10 kHz． If the pulse of lightning current arises faster，the amplitude of frequency component will be smaller，but the more high － frequency components are contained．