同轴线中雷电波传输暂态特性的分析

Study on the Transient Transmission Characteristics of the Lightning Wave in Coaxial Cable

针对同轴线中雷电波传输特性的问题,通过对同轴波导暂态响应和非均匀传输线理论进行分析,采用冲击电压波发生器来模拟1. 2/50μs雷电波进行试验。得出:雷电波在均匀同轴线中几乎不发生畸变,波形衰减不明显,但在并联气体放电管(Gas Discharge Tube,GDT)的同轴线中发生了畸变,出现不同程度的振荡,产生高次模;随着同轴线长度的增加,雷电波畸变的程度逐渐变小,高次模出现的频率逐渐减少,波形振荡的周期也越来越少;在不同位置并联相同气体放电管,距离输出端越远其振荡幅值越大,其中高次模的成分越丰富,振荡周期越多,振荡持续的时间越长。同时对1. 2/50μs雷电波的幅值、负载以及同轴线中并联的气体放电管的数量等因素进行详细地讨论。这在实际雷电防护应用中,具有一定的指导意义和价值。

For the issue of transient transmission characteristics of lightning wave in coaxial cable,the transient process in a coaxial cable and theory of non-uniform transmission line are analyzed. The 1. 2/50 μs lightning wave is adopted to carry out the test on coaxial cable. The conclusions can be drawn as follows,coaxial cable without the connection Gas Discharge Tube( GDT) in paroled,there are no distortion and no attenuation of wave;but coaxial cable with the connection GDT in paroled,the distortion and oscillation of wave are occurred,and the higher order modes is also emitted;The distortion of lightning wave,the occurrence frequency of higher order modes and the period of oscillation decrease with the length of coaxial cable increasing;the oscillation greater the farther they are from output,the more abundant the higher order modes,the more number the period of oscillation,and the longer the time of oscillation when GDTs are paroled with different locations. Various amplitude of 1. 2/50 μs lightning wave,various loads and the number of GDT paroled in coaxial cable are also discussed in detail. It has significance in the practical application of signal transmission in lightning protection.